Methods of forming block polymers for directed self-assembly

ABSTRACT

Block polymers are formed by ring opening polymerization (ROP) of a cyclic carbonate monomer using a polymeric initiator for the ROP that comprises repeating functionalized ethylene units. The block polymers are free of, or substantially free of, any polymer having a chemical structure that does not comprise the polymer backbone of the polymeric initiator. The block polymers are capable of directed self-assembly.

BACKGROUND

The present invention relates to methods of forming block polymers fordirected self-assembly applications, more specifically methods of makinghigh-chi (χ) block polymers prepared by ring opening of cyclic carbonylmonomers.

Block copolymers (BCPs) find many applications in solution, bulk andthin films. Thin film applications of BCPs are particularly attractivefor nanolithography and patterning due to the ability of some BCPs toform periodic self-assembled structures ranging in feature size from 5nm to 50 nm. The thin-film self-assembly property of BCPs can beutilized with existing photolithographic techniques to provide a uniqueapproach to long range order for semiconductor applications. Thisapproach, called directed self-assembly (DSA) of block copolymers,promises to extend the patterning capabilities of conventionallithography.

BCPs for directed self-assembly (DSA) applications comprise two or threepolymer blocks that can phase separate into ordered nanoscopic arrays ofspheres, cylinders, gyroids, and lamellae. The ability of a BCP to phaseseparate depends on the Flory Huggins interaction parameter (χ).PS-b-PMMA is the most widely used block copolymer for DSA. However, theminimum half-pitch of PS-b-PMMA is limited to about 10 nm because oflower interaction and interaction parameter (χ) between PS and PMMA. Toenable further feature miniaturization, a block copolymer with higherinteraction parameter between two blocks (higher chi) is highlydesirable.

Several block copolymers having higher interaction parameter between thetwo blocks have been studied to obtain smaller feature sizes. Ofparticular interest are block copolymers comprising a block derived fromring opening of a cyclic carbonyl monomer from a reactive end-group onthe first polymer block. Block copolymers derived by ring openingpolymerization (ROP) of cyclic monomers (e.g., lactides, lactams,lactones, ethylene oxide) have been used to generate sub-10 nm featuresize for patterning applications.

In the case of ring opening polymerizations (ROP) of cyclic carbonylmonomers, several side reactions can occur. For example, ROP of cyclicester monomers (i.e., lactides and/or lactones) can includetransesterification reactions and/or end group backbiting reactions(Macromolecules, 1998, 31, 2114) that can degrade the polyesterbackbone, broaden the molecular weight distribution of the blockcopolymer, and/or form residual free polyester chains and/or cyclicpolyester oligomers. Similar side reactions can occur in ring openingpolymerization of cyclic carbonates that can significantly broaden themolecular weight distribution and ultimately lead to bimodal GPC traces(Macromolecules, 2011, 44 (7), pp 2084-2091). The presence of moistureor other nucleophilic impurities either in the cyclic carbonyl monomer,reaction solvent, catalyst, and/or the initiator can also form ringopened oligomers or ROP homopolymers in addition to the desired blockcopolymers (Macromolecules 2010, 43, 8828-8835). Oftentimes the cyclicoligomers or homopolymers formed as side reactions cannot be easilyseparated from the block copolymers, resulting in poor thin-filmself-assembly behavior. For good thin-film self-assembly, blockcopolymers that are free of homopolymer and that have low polydispersityindex (PDI) are preferred.

Thus, there exists a need for methods of forming ROP based blockcopolymers for self-assembly applications that minimize the amount ofhomopolymer, cyclic oligomer and other byproducts derived from ringopening of cyclic carbonyl monomer.

SUMMARY

Accordingly, a method is disclosed, comprising:

forming a reaction mixture for a ring opening polymerization (ROP), thereaction mixture comprising a cyclic carbonyl monomer, a polymericinitiator for the ROP, a ROP catalyst, and a solvent, wherein thepolymeric initiator comprises i) a polymer backbone comprising repeatingfunctionalized ethylene units and ii) 1 to 2 nucleophilic groups capableof initiating a ROP of the cyclic carbonyl monomer;

allowing the cyclic carbonyl monomer to polymerize by ROP until 85% ormore of the cyclic carbonyl monomer is consumed, thereby forming asecond mixture comprising an initial block polymer, wherein the initialblock polymer comprises a first block linked to a second block, thefirst block comprising the polymer backbone comprising repeatingfunctionalized ethylene units, the second block comprising a backbonederived from ROP of the cyclic carbonyl monomer;

precipitating the initial block polymer in a solvent mixture comprisingi) a first solvent which is a non-solvent for the first block, and ii) asecond solvent comprising a nitrile group, wherein the firstsolvent:second solvent volume ratio is about 40:60 to about 60:40,thereby forming a final block polymer that is free of, or substantiallyfree of, any polymer having a chemical structure that contains none ofthe polymer backbone of the polymeric initiator.

Another method is disclosed, comprising:

A method, comprising:

i) providing a mathematical function F(t) for a ring openingpolymerization (ROP) of a cyclic carbonyl monomer, wherein

-   -   F(t) expresses an amount of consumed cyclic carbonyl monomer as        a function of ROP duration time t for given reaction conditions,    -   the ROP utilizes a reaction mixture initially comprising the        cyclic carbonyl monomer, a polymeric initiator for the ROP, a        ROP catalyst, and a solvent,    -   the polymeric initiator comprises i) a polymer backbone        comprising repeating functionalized ethylene units and ii) 1 to        2 nucleophilic groups linked to respective end groups of the        polymer backbone, the nucleophilic groups capable of initiating        the ROP of the cyclic carbonyl monomer,    -   F(t) has a duration time t₁>0 corresponding to 50% consumption        of the cyclic carbonyl monomer,    -   F(t) has duration times t₂ and t₃ wherein t₃>t₂>t₁,        -   F(t) has a first derivative designated F′(t),        -   F′(t) at t₁ has a value F′(t₁)=m, wherein m is a number >0,        -   F′(t) at t₂ has a value F′(t₂)=0.9 m, and        -   F′(t) at t₃ has a value F′(t₃)=0.8 m;    -   ii) conducting the ROP of the cyclic carbonyl monomer using the        given set of reaction conditions; and    -   iii) stopping the ROP at a ROP duration time of about t₁ to        about t₃, thereby forming a second mixture comprising a final        block polymer capable of self-assembly, wherein the final block        polymer comprises a first block linked to a second block, the        first block comprising the polymer backbone comprising repeating        functionalized ethylene units, the second block comprising a        backbone derived from ROP of the cyclic carbonyl monomer, and        wherein the second mixture is free of, or substantially free of,        any polymer having a chemical structure that contains none of        the polymer backbone of the polymeric initiator.

Another method is disclosed, comprising:

A method, comprising:

i) providing a mathematical function F(t) for a ring openingpolymerization (ROP) of a cyclic carbonyl monomer, wherein

-   -   F(t) expresses an amount of consumed cyclic carbonyl monomer as        a function of ROP duration time t for given reaction conditions,    -   the ROP utilizes a reaction mixture initially comprising the        cyclic carbonyl monomer, a polymeric initiator for the ROP, a        ROP catalyst, and a solvent,    -   the polymeric initiator comprises i) a polymer backbone        comprising repeating functionalized ethylene units and ii) 1 to        2 nucleophilic groups linked to respective end groups of the        polymer backbone, the nucleophilic groups capable of initiating        the ROP of the cyclic carbonyl monomer, and    -   F(t) has a first derivative F′(t);

ii) providing a mathematical function D(t) expressing change in F′(t)between adjacent ROP duration times, designated ΔF′(t), as a function ofROP duration time t, wherein i) ΔF′(t_(n))=F′(t_(n))−F′(t_(n-1)) foradjacent duration times t_(n) and t_(n-1), t_(n)>t_(n-1), and n is apositive integer greater than or equal to 1, ii) D(t) has a firstderivative designated D′(t), and iii) D′(t) has a duration time t′>0wherein D′(t′)=0;

iii) conducting the ROP of the cyclic carbonyl monomer using the givenreaction conditions; and

iv) stopping the ROP at a polymerization duration time of 0.8t′ to t′,thereby forming a second mixture comprising a final block polymercapable of self-assembly, wherein the final block polymer comprises afirst block comprising the polymer backbone comprising repeatingfunctionalized ethylene units, the first block being linked by a polymerchain end group to a second block comprising a polymer backbone derivedfrom the cyclic carbonyl monomer, and wherein the second mixture issubstantially free of any polymer having a chemical structure thatcontains none of the polymer backbone of the polymeric initiator.

Also disclosed is a method of forming a layered structure, comprising

forming a mixture comprising a solvent and the above-described finalblock polymer;

applying the mixture to a pre-patterned surface of a substrate, therebyforming a first structure, the pre-patterned surface capable of guidingself-assembly of the final block polymer wherein self-assembly of thefinal block polymer comprises phase separation of a first block of thefinal block polymer from a second block of the final block polymer toform first domains comprising the first block and second domainscomprising the second block, the first domains not being miscible withthe second domains;

removing the solvent from the first structure, thereby forming a secondstructure comprising the final block polymer disposed on the surface ofthe substrate; and

allowing the final block polymer of the second structure toself-assemble, optionally assisted with heat, thereby forming thelayered structure, the layered structure comprising the self-assembledfinal block polymer disposed on the pre-patterned surface.

The above-described and other features and advantages of the presentinvention will be appreciated and understood by those skilled in the artfrom the following detailed description, drawings, and appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a graph of the polynomial trendline F(t) expressing percentconsumption of trimethylene carbonate (TMC) as a function of ROPduration time t in minutes for the reaction conditions used in Example44.

FIG. 2 is a graph of the first derivative F′(t) of the polynomialfunction shown in FIG. 1.

FIG. 3 is a graph of the second order polynomial trendline D(t) obtainedfor a scatter plot of ΔF′(t) as a function oft for Example 44.

FIGS. 4A-4E are cross-sectional layer diagrams illustrating a process offorming a self-assembled block polymer layer disposed on a substrate bygraphoepitaxy.

FIGS. 5A-5D are cross-sectional layer diagrams illustrating a process offorming a self-assembled block polymer layer disposed on a substrate bychemical epitaxy.

FIG. 6 is a proton NMR spectrum of the TMC after drying withAbderhalden's drying apparatus (Example 3).

FIG. 7 is a proton NMR spectrum of the TMC after three recrystallizationcycles (Example 4).

FIG. 8 is a GPC trace of the block polymer of Example 12 beforefractionation, in which TMC conversion was 99%.

FIG. 9 is a GPC trace of the block polymer of Example 13 beforefractionation, in which TMC conversion was 94%.

FIG. 10 is a GPC trace of the block polymer of Example 20 beforefractionation, in which TMC conversion was 50%.

FIG. 11 is a GPC trace of Example 23 after fractionating the blockpolymer of Example 12 using methanol:acetonitrile 80:20 v/v.

FIG. 12 is a GPC trace of Example 24 after fractionating the blockpolymer of Example 12 using methanol:acetonitrile 60:40 v/v.

FIG. 13 is a GPC trace of Example 25 after fractionating the blockpolymer of Example 12 using methanol:acetonitrile 40:60 v/v.

FIG. 14 is a GPC trace of Example 26 after fractionating the blockpolymer of Example 13 using methanol:acetonitrile 40:60 v/v.

FIG. 15 is a GPC trace of Example 33 after fractionating the blockpolymer of Example 20 using methanol:acetonitrile 60:40 v/v.

FIG. 16 is an AFM height image of the as-cast film prepared in Example40 using block polymer PS-b-PTMC from Example 13 (not-fractionated).

FIG. 17 is an AFM height image of an annealed film prepared in Example40 using PS-b-PTMC from Example 13.

FIG. 18 is an AFM height image of the as-cast film prepared in Example41 using PS-b-PTMC from Example 26.

FIG. 19 is an AFM height image of an annealed film prepared in Example41 using PS-b-PTMC from Example 26.

FIG. 20 is an AFM image of the as-cast film of Example 45 formed withthe block polymer of Example 17.

FIG. 21 is an AFM image of the as-cast film of Example 46 formed withthe block polymer of Example 20.

FIG. 22 is an AFM image of the as-cast film of Example 47 formed withthe block polymer of Example 21.

FIG. 23 is an AFM image of the as-cast film of Example 48 formed withthe block polymer of Example 31.

FIG. 24 is an AFM image of the as-cast film of Example 49 formed withthe block polymer of Example 33.

FIG. 25 is an AFM image of the as-cast film of Example 50 formed withthe block polymer of Example 34.

FIG. 26 is a layer diagram depicting the coated structure of Example 51containing the self-assembled block polymer.

FIG. 27 is an SEM image of the structure of Example 51 after etching.

FIG. 28 is a top down view of a diagram of the structure of Example 51before etching.

FIG. 29 is a top down view of a diagram of the structure of Example 51after etching.

DETAILED DESCRIPTION

The disclosed methods provide block polymers for directed self-assemblythat are substantially free of non-block polymer contaminants thatadversely influence the self-assembly properties of the block polymer.The block polymers are also referred to herein as “final block polymers”to distinguish them from an initial block polymer that can containpolymer impurities that adversely affect self-assembly properties.

The final block polymers comprise i) a first block comprising a firstpolymer backbone comprising repeating functionalized ethylene units(e.g., a backbone comprising repeating units derived from a vinylpolymerizable monomer wherein R¹R² are suitable pendant groups such as,for example hydrogen, alkyl, aryl, and alkoxycarbonyl) and ii) a secondblock comprising a second polymer backbone formed by ring openingpolymerization (ROP) of one or more cyclic carbonyl monomers.“Functionalized ethylene units” of the polymer backbone are ethyleneunits having the structure *-[CH₂—C(R¹)(R²)]-* comprising pendant groupsR¹ and/or R² (e.g., hydrogen, benzene, methyl, and methoxycarbonylpendant groups), which can result from vinyl polymerization of styrene,methacrylates, and/or acrylates, and so on. The cyclic carbonyl monomersare preferably selected from the group consisting of cyclic carbonatemonomers, cyclic ester monomers, and combinations thereof

The final block polymers preferably have 2 or 3 blocks arranged end toend in a linear, non-cyclic polymer chain. For example, a diblockpolymer has an A polymer block and a B polymer block of differentcompositions linked together as A-B. A triblock polymer has an A block,a B block and a C block arranged in a linear, non-cyclic polymer chainas A-B-A. The central block B of the triblock polymer has a differentchemical composition from the two peripheral monovalent blocks A. Forexample, the central block B can comprise the first polymer backbonecomprising repeating functionalized ethylene units, and the twoperipheral blocks A can comprise polymer backbones formed sequentiallyor simultaneously by ring opening polymerization (ROP) of one or morecyclic carbonyl monomers. Alternatively, the central block B cancomprise a first polymer backbone formed by ring opening polymerization(ROP) of one or more cyclic carbonyl monomers, and the two peripheralblocks A can comprise polymer backbones formed sequentially orsimultaneously using one or more vinyl polymerizable monomers. Theperipheral monovalent blocks A of the A-B-A triblock polymer can havethe same or different repeat units.

The following discussion is directed to diblock polymers (A-B) but canbe applied to triblock polymers.

The first block (having a backbone comprising repeating functionalizedethylene units) and the second block (derived from a cyclic carbonylmonomer) are selected so as to be substantially immiscible with oneanother. Additionally, the first block and the second block of the finalblock polymer have the following solubility properties with respect to asolvent mixture used to precipitate the final block polymer: i) thefirst block and the second block are substantially insoluble in a firstsolvent of the solvent mixture, ii) the first block is substantiallyinsoluble in a second solvent of the solvent mixture, and iii) thesecond block is soluble in a second solvent of the solvent mixture. Thatis, the first solvent is a non-solvent for the first block and thesecond block, the second solvent is a non-solvent for the first block,and the second solvent is a solvent for the second block.

The specific structural units formed by self-assembly of the final blockpolymer are determined by the volume ratio of the first block to thesecond block. The volume of a given block means the volume occupied bythe block, which depends on molecular mass of the block. For example,when the volume ratio of the first block to the second block component Bis greater than about 80:20, the final block polymer can form an orderedarray of spheres composed of the second block in a matrix composed ofthe first block. When the volume ratio of the first block to the secondblock is in a range of about 80:20 to about 60:40, the final blockpolymer can form an ordered array of cylinders composed of the secondblock in a matrix composed of the first block. When the volume ratio ofthe first block to the second block is less than about 60:40 to about40:60, the final block polymer can form alternating lamellae (i.e.,domains composed of the first block alternating with domains composed ofthe second block). The volume ratio between the first block and thesecond block can be adjusted by controlling the average molecular weightof each block.

More specifically, the volume ratio of the first block to second blockcan be about 15:85 to about 85:15, based on the average total volume ofthe final block polymer macromolecule. For alternating lamellaeformation, the volume ratio of the first block to second block can beabout 40:60 to about 60:40, more preferably 45:55 to 55:45, and mostpreferably 48:52 to 52:48. For cylinder formation, the volume ratio ofthe first block to second block can be about 74:26 to about 63:37, andmore preferably about 72:28 to about 65:35.

One of the blocks of the final block polymer can be selectively removed(e.g., by lithographic etching techniques) relative to the other blockto form structural features composed of the remaining block. Thestructural features can have any suitable form such as, for example, aline pattern, a hole pattern, and/or other patterns.

The ROP polymeric initiator can be the product of a vinylpolymerization. Vinyl polymerizable monomers include styrenes,acrylates, methacrylates, substituted derivatives thereof, and the like.The vinyl polymerizable monomers can be used singularly or incombination to form the ROP polymeric initiator using any suitablepolymerization technique, including but not limited to free radicalpolymerization, anionic polymerization, cationic polymerization, atomtransfer radical polymerization (ATRP), nitroxide mediatedpolymerization (NMP), and/or reversible addition-fragmentation chaintransfer (RAFT) polymerization.

The final block polymers are preferably formed by conducting a ROP of acyclic carbonyl monomer using a pre-formed polymeric initiator for theROP that has a polymer backbone derived from a vinyl polymerizablemonomer. The polymeric initiator also comprises 1 or 2 nucleophilicgroups (e.g., *-OH, *-NH₂) capable of initiating the ROP of the cycliccarbonyl monomer. The ROP reaction mixture comprises a cyclic carbonylmonomer, a ROP catalyst, a solvent, and the polymeric initiator. The ROPcatalyst is preferably an acid catalyst (e.g., diphenyl phosphate).

The following methods of forming a diblock polymer can be applied to thepreparations of triblock polymers. The methods arise from the discoverythat the polymeric impurities described above are substantially formedin the later stages of the ROP, when more than 50% of the cycliccarbonyl monomer has been consumed.

Method 1

This method utilizes a solvent mixture to fractionate the initial blockpolymer formed when the ROP is conducted for a duration timecorresponding to about 50% to 100%, more particularly about 85% to 100%consumption of the cyclic carbonyl monomer. For a given set of reactionconditions (e.g., temperature, solvent, type of atmosphere, relativemolar amounts, and other reaction parameters), the consumption of thecyclic carbonyl monomer can be monitored using any suitable analyticaltechnique (e.g., proton nuclear magnetic resonance (¹H NMR)).

The ROP produces an initial block polymer containing a living end group,which is a nucleophilic group capable of undergoing further chain growthand/or initiating a ROP of a different cyclic carbonyl monomer.Preferably, the active living end group is deactivated by addition of anendcapping agent to the reaction mixture, thereby terminating thepolymerization and forming an endcapped initial block polymer containinga protected nucleophilic end group. The endcapped initial block polymeris not capable of initiating a ROP. As an example, a polycarbonateformed by ROP of a cyclic carbonate monomer has a living end containinga nucleophilic hydroxy group, which can be deactivated by addition of asuitable acylating agent (e.g., acetic anhydride) to form a protectedhydroxy group (e.g., as an ester). The isolated initial block polymer orthe endcapped initial block polymer (“crude block polymer”) can containpolymeric impurities derived from the cyclic carbonyl monomer that arenot covalently linked to the polymeric initiator. Polymeric impuritiescan include polycarbonate homopolymer initiated by traces of water,and/or cyclic polycarbonate formed by backbiting of the living hydroxyend group on the polycarbonate backbone of the initial block polymer.These impurities can adversely affect the self-assembly properties ofthe initial block polymer.

The polymeric impurities can be removed by the following fractionationprocess. A first solution is prepared containing the initial blockpolymer dissolved in a minimal amount of a solvent (e.g., THF) capableof dissolving each block of the block polymer. The first solutioncontains the initial block polymer at a concentration of about 20 wt %based on total weight of the first solution. The first solution is thenadded to an excess amount (about 200 to 400 times the amount of crudepolymer by weight) of a solvent mixture comprising a first solvent and asecond solvent in a volume ratio of about 40:60 to about 60:40,respectively, wherein the first solvent is a non-solvent for the firstblock and the second block, and the second solvent that is a non-solventfor the first block and a solvent for the second block. In anembodiment, the first solvent is MeOH and the second solvent isacetonitrile. The solvent mixture selectively dissolves the polymericimpurities, allowing the final block polymer to precipitate as a solidthat can be substantially free of the polymeric impurities. Thefractionation procedure can be repeated one or more times as necessaryto form a final block polymer for self-assembly applications.

Method 2

In a second method, a trial ROP is performed using the given set ofreaction conditions that includes the polymeric initiator. The amount ofconsumed cyclic carbonyl monomer is monitored (e.g., % consumption) as afunction of ROP duration time t as in Method 1, allowing the ROP toproceed to 85% to 100% consumption of the cyclic carbonyl monomer. As anexample, FIG. 1 is a graph of the percent consumption of trimethylenecarbonate (TMC) as a function of ROP duration time t in minutes observedfor reaction conditions used in Example 44 further below.

From the scatter plot of the collected data points, a second orderpolynomial function F(t) (i.e., a trendline) can be fitted to theplotted points, wherein F(t) expresses the amount of consumed cycliccarbonyl monomer as a function of ROP duration time t. For the datapoints of FIG. 1, F(t)=−0.00005t²+0.1352t, having R²=0.9993. R²(R-squared) is the coefficient of determination and indicates how wellthe data points fit the trendline F(t). R-squared preferably has a valueof about 0.85 to 1.0, more preferably 0.9 to 1.0.

Using the expression of F(t), a time t₁ corresponding to 50% consumptionof the cyclic carbonyl monomer can be calculated. In this instance50=−0.00005t₁ ²+0.1352t₁, and t₁ has a value of 442 minutes using thequadratic formula to obtain the roots.

The expression F(t) has a first derivative, denoted F′(t). For Example44, F′(t)=−0.0001t+0.1352, a line (FIG. 2). Table 13 below lists thevalues of F′(t) calculated for each measurement time t.

The value of F′(t) at 50% cyclic monomer conversion can then becalculated. For Example 44, the value of F′(t) at t₁=442 minutes isF′(442)=−0.0001(442)+0.1352=0.091. Using the value of F′(t) at 50%cyclic monomer conversion, ROP duration times t₂ and t₃ are calculated,which correspond to 90% of F′(442) and 80% of F′(442), respectively.That is, the duration times are determined corresponding to a slopechange of −10% and −20% relative to the slope at 50% consumption ofcyclic carbonyl monomer. For Example 44, 90% of F′(442) has a value of0.9(0.091)=0.0819, which corresponds to a reaction time of 533 minutes(t₂=533 minutes), and 80% of F′(442) has a value of 0.8(0.091)=0.0728,which corresponds to a reaction time of 624 minutes (t₃=624 minutes).

The ROP is repeated using the given reaction conditions, stopping theROP at duration time (t′), wherein t₁≦t′≦t₃ (i.e., about 422 minutes toabout 624 minutes in Example 44), and more preferably t₂≦t′≦t₃ (i.e.,about 533 minutes to about 624 minutes in Example 44). Using thesemodified reaction conditions, a final block polymer for self-assemblycan be obtained directly that is free of, or substantially free of,polymer impurities that do not comprise a block derived from thepolymeric initiator. Optionally, the block polymer can be furthertreated with the solvent mixture as described above under Method 1 toremove any remaining polymeric impurities.

Method 3

In Method 3, the mathematical expression for F′(t) is obtained asdescribed above under Method 2. The value of F′(t) is then calculatedfor each ROP duration time t. Using the values of F′(t), the change inF′(t) between adjacent ROP duration times is calculated for each ROPduration time greater than 0. For example, the change in F′(t) atduration time t_(n), denoted as ΔF′(t_(n)), is equal toF′(t_(n))−F′(t_(n-1)), where n is a positive integer and t_(n)>0. Table14 below lists ΔF′(t) at each duration time t for Example 44.

A second order polynomial trendline D(t) is obtained for a scatter plotof ΔF′(t) as a function of t, shown in FIG. 3 for Example 44. In thisinstance, trendline D(t) has the shape of an inverted parabola, whereinD(t)=−0.0000001t²+0.0002t−0.0562, having an R-squared value of 0.8885.D(t) has a first derivative D′(t) equal to zero at a ROP duration timet″>0 which is less than the duration time corresponding to 100%consumption of the cyclic carbonyl monomer. For Example 44, D′(t)=0 atabout 630 minutes (i.e., t″=630 minutes).

The ROP is repeated using the given reaction conditions, terminating theROP at 0.8t″ to about t″ (about 504 minutes to about 630 minutes). Theresulting final block polymer can be free of, or substantially free of,polymer impurities that do not comprise a block derived from thepolymeric initiator. Optionally, the final block polymer can be furthertreated with the solvent mixture as described above under Method 1 toremove any polymeric impurities present.

Cyclic Carbonyl Monomers

A polymer block derived from cyclic carbonyl monomer can be ahomopolymer or a random copolymer. The cyclic carbonyl monomers can bestereospecific or non-stereospecific.

Exemplary cyclic carbonyl monomers include cyclic carbonate compounds ofTable 1, which can be used, for example, to form a polycarbonate blockof the initial block polymer.

TABLE 1

Other cyclic carbonyl monomers include cyclic esters (lactones), such asthe compounds of Table 2.

TABLE 2

The above cyclic carbonyl monomers can be purified by recrystallizationfrom a solvent such as ethyl acetate or by other known methods ofpurification, with particular attention being paid to removing as muchwater as possible from the monomer.

ROP Initiators

Initiators for ring opening polymerizations generally includenucleophilic groups such as alcohols, primary amines, secondary amines,and thiols. Herein, the ROP initiator is a polymeric initiatorcomprising a polymer backbone derived from a polymerizable vinyl monomer(styrenes, methacrylates, acrylates, methacrylamides, acrylamides, vinylesters). An exemplary polymeric intiator is the functionalizedpolystyrene initiator PS—OH shown below.

The polymeric initiator preferably comprises one or two nucleophilichydroxy groups for initiating a ROP and forming diblock and triblockpolymers, respectively. The number average molecular weight of thepolymeric initiator can be from 1000 to 1,000,000, more specifically1000 to 100,000, and even more specifically, 1000 to 50,000.

Ring Opening Polymerizations (ROP)

The following description of methods, conditions and materials for ringopening polymerizations is applicable to the preparation of the finalblock polymer.

The ring-opening polymerization can be performed at a temperature thatis about ambient temperature or higher, 15° C. to 100° C., and morespecifically ambient temperature. Reaction times vary with solvent,temperature, agitation rate, pressure, and equipment, but in general thepolymerizations are complete within about 1 hour to about 48 hours.

The ROP reaction can be performed with or without the use of a solvent.Optional solvents include dichloromethane, chloroform, benzene, toluene,xylene, chlorobenzene, dichlorobenzene, benzotrifluoride, petroleumether, acetonitrile, pentane, hexane, heptane, 2,2,4-trimethylpentane,cyclohexane, diethyl ether, t-butyl methyl ether, diisopropyl ether,dioxane, tetrahydrofuran, or a combination comprising one of theforegoing solvents. When a solvent is present, a suitable monomerconcentration is about 0.1 to 5 moles per liter, and more particularlyabout 0.2 to 4 moles per liter.

Whether performed in solution or in bulk, the ROP polymerizations areconducted using an inert (i.e., dry) atmosphere, such as nitrogen orargon, and at a pressure of from 100 to 500 MPa (1 to 5 atm), moretypically at a pressure of 100 to 200 MPa (1 to 2 atm). At thecompletion of the reaction, the solvent can be removed using reducedpressure.

ROP Catalysts

No restriction is placed on the ROP catalyst. Exemplary catalysts forthe ROP polymerization include metal oxides such as tetramethoxyzirconium, tetra-iso-propoxy zirconium, tetra-iso-butoxy zirconium,tetra-n-butoxy zirconium, tetra-t-butoxy zirconium, triethoxy aluminum,tri-n-propoxy aluminum, tri-iso-propoxy aluminum, tri-n-butoxy aluminum,tri-iso-butoxy aluminum, tri-sec-butoxy aluminum,mono-sec-butoxy-di-iso-propoxy aluminum, ethyl acetoacetate aluminumdiisopropylate, aluminum tris(ethyl acetoacetate), tetraethoxy titanium,tetra-iso-propoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxytitanium, tetra-sec-butoxy titanium, tetra-t-butoxy titanium,tri-iso-propoxy gallium, tri-iso-propoxy antimony, tri-iso-butoxyantimony, trimethoxy boron, triethoxy boron, tri-iso-propoxy boron,tri-n-propoxy boron, tri-iso-butoxy boron, tri-n-butoxy boron,tri-sec-butoxy boron, tri-t-butoxy boron, tri-iso-propoxy gallium,tetramethoxy germanium, tetraethoxy germanium, tetra-iso-propoxygermanium, tetra-n-propoxy germanium, tetra-iso-butoxy germanium,tetra-n-butoxy germanium, tetra-sec-butoxy germanium and tetra-t-butoxygermanium; halogenated compounds such as antimony pentachloride, zincchloride, lithium bromide, tin(IV) chloride, cadmium chloride and borontrifluoride diethyl ether; alkyl aluminum such as trimethyl aluminum,triethyl aluminum, diethyl aluminum chloride, ethyl aluminum dichlorideand tri-iso-butyl aluminum; alkyl zinc such as dimethyl zinc, diethylzinc and diisopropyl zinc; tertiary amines such as triallylamine,triethylamine, tri-n-octylamine and benzyldimethylamine; heteropolyacidssuch as phosphotungstic acid, phosphomolybdic acid, silicotungstic acidand alkali metal salts thereof; zirconium compounds such as zirconiumacid chloride, zirconium octanoate, zirconium stearate and zirconiumnitrate. More particularly, the catalyst is zirconium octanoate,tetraalkoxy zirconium or a trialkoxy aluminum compound.

Other ROP catalysts are organocatalysts whose chemical formula containsno metal. Base organocatalysts for ROPs of cyclic carbonyl monomersinclude tertiary amines such as triallylamine, triethylamine,tri-n-octylamine and benzyldimethylamine 4-dimethylaminopyridine,phosphines, N-heterocyclic carbenes (NHC), bifunctional aminothioureas,phosphazenes, amidines, and guanidines.

A thiourea ROP organocatalyst isN-(3,5-trifluoromethyl)phenyl-N′-cyclohexyl-thiourea (TU):

Other ROP organocatalysts comprise at least one1,1,1,3,3,3-hexafluoropropan-2-ol-2-yl (HFP) group. Singly-donatinghydrogen bond catalysts have the formula (1):

R²—C(CF₃)₂OH  (1),

wherein R² represents a hydrogen or a monovalent radical having from 1to 20 carbons, for example an alkyl group, substituted alkyl group,cycloalkyl group, substituted cycloalkyl group, heterocycloalkyl group,substituted heterocycloalklyl group, aryl group, substituted aryl group,or a combination thereof. Exemplary singly-donating hydrogen bondingcatalysts are listed in Table 3.

TABLE 3

Doubly-donating hydrogen bonding catalysts have two HFP groups,represented by the general formula (13):

wherein R³ is a divalent radical bridging group containing from 1 to 20carbons, such as an alkylene group, a substituted alkylene group, acycloalkylene group, substituted cycloalkylene group, aheterocycloalkylene group, substituted heterocycloalkylene group, anarylene group, a substituted arylene group, and a combination thereof.Representative double hydrogen bonding catalysts of formula (2) includethose listed in Table 4. In a specific embodiment, R² is an arylene orsubstituted arylene group, and the HFP groups occupy positions meta toeach other on the aromatic ring.

TABLE 4

Preferred hydrogen bonding catalysts include 4-HFA-St, 4-HFA-Tol, HFTB,NFTB, HPIP, 3,5-HFA-MA, 3,5-HFA-St, 1,3-HFAB, 1,4-HFAB, and combinationsthereof

The HFP catalyst can be bound to a support. In one embodiment, thesupport comprises a polymer, a crosslinked polymer bead, an inorganicparticle, or a metallic particle. HFP-containing polymers can be formedby known methods including direct polymerization of an HFP-containingmonomer (for example, the methacrylate monomer 3,5-HFA-MA or the styrylmonomer 3,5-HFA-St). Functional groups in HFP-containing monomers thatcan undergo direct polymerization (or polymerization with a comonomer)include acrylate, methacrylate, alpha, alpha,alpha-trifluoromethacrylate, alpha-halomethacrylate, acrylamido,methacrylamido, norbornene, vinyl, vinyl ether, and other groups knownin the art. Examples of linking groups include C₁-C₁₂ alkyl, a C₁-C₁₂heteroalkyl, ether group, thioether group, amino group, ester group,amide group, or a combination thereof. Also contemplated are catalystscomprising charged HFP-containing groups bound by ionic association tooppositely charged sites on a polymer or a support surface.

Most preferably, the ROP catalyst is an acid organocatalyst (e.g.,diphenylphosphate (DPP), triflic acid).

The ROP reaction mixture comprises at least one ROP catalyst and, whenappropriate, several ROP catalysts together. The ROP catalyst is addedin a proportion of 1/20 to 1/40,000 moles relative to the cycliccarbonyl monomers, and preferably in a proportion of 1/1,000 to 1/20,000moles relative to the cyclic carbonyl monomers.

ROP Accelerators.

The ROP polymerization can be conducted in the presence of an optionalaccelerator, in particular a nitrogen base. Exemplary nitrogen baseaccelerators are listed below and include pyridine (Py),N,N-dimethylaminocyclohexane (Me₂NCy), 4-N,N-dimethylaminopyridine(DMAP), trans 1,2-bis(dimethylamino)cyclohexane (TMCHD),1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD),7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), (−)-sparteine, (Sp)1,3-bis(2-propyl)-4,5-dimethylimidazol-2-ylidene (Im-1),1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (Im-2),1,3-bis(2,6-di-i-propylphenyl(imidazol-2-ylidene (Im-3),1,3-bis(1-adamantyl)imidazol-2-ylidene (Im-4),1,3-di-i-propylimidazol-2-ylidene (Im-5),1,3-di-t-butylimidazol-2-ylidene (Im-6),1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene (Im-7),1,3-bis(2,6-di-i-propylphenyl)-4,5-dihydroimidazol-2-ylidene,1,3-bis(2,6-di-i-propylphenyl)-4,5-dihydroimidazol-2-ylidene (Im-8) or acombination thereof, shown in Table 5.

TABLE 5

In an embodiment, the accelerator has two or three nitrogens, eachcapable of participating as a Lewis base, as for example in thestructure (−)-sparteine. Stronger bases generally improve thepolymerization rate.

The catalyst and the accelerator can be the same material. For example,some ring opening polymerizations can be conducted using1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) alone, with no another catalystor accelerator present.

The catalyst is preferably present in an amount of about 0.2 to 20 mol%, 0.5 to 10 mol %, 1 to 5 mol %, or 1 to 2.5 mol %, based on totalmoles of cyclic carbonyl monomer.

The nitrogen base accelerator, when used, is preferably present in anamount of 0.1 to 5.0 mol %, 0.1 to 2.5 mol %, 0.1 to 1.0 mol %, or 0.2to 0.5 mol %, based on total moles of cyclic carbonyl monomer. As statedabove, in some instances the catalyst and the nitrogen base acceleratorcan be the same compound, depending on the particular cyclic carbonylmonomer.

The amount of initiator is calculated based on the equivalent molecularweight per nucleophilic initiator group in the dinucleophilic initiator.The initiator groups are preferably present in an amount of 0.001 to10.0 mol %, 0.1 to 2.5 mol %, 0.1 to 1.0 mol %, and 0.2 to 0.5 mol %,based on total moles of cyclic carbonyl monomer. For example, if themolecular weight of the initiator is 100 g/mole and the initiator has 2hydroxyl groups, the equivalent molecular weight per hydroxyl group is50 g/mole. If the polymerization calls for 5 mol % hydroxyl groups permole of monomer, the amount of initiator is 0.05×50=2.5 g per mole ofmonomer.

In a specific embodiment, the catalyst is present in an amount of about0.2 to 20 mol %, the nitrogen base accelerator is present in an amountof 0.1 to 5.0 mol %, and the nucleophilic initiator groups of theinitiator are present in an amount of 0.1 to 5.0 mol % based on theequivalent molecular weight per nucleophilic initiator group of theinitiator.

The catalysts can be removed by selective precipitation or in the caseof the solid supported catalysts, simply by filtration. The blockpolymer can comprise residual catalyst in an amount greater than 0 wt %(weight percent), based on total weight of the block copolymer and theresidual catalyst. The amount of residual catalyst can also be less than20 wt %, less than 15 wt %, less than 10 wt %, less than 5 wt %, lessthan 1 wt %, or most specifically less than 0.5 wt % based on the totalweight of the block copolymer and the residual catalyst.

Endcap Agents

An endcap agent can prevent further chain growth and stabilize thereactive end groups from unwanted side reactions, such as chainscission. Endcap agents include, for example, compounds for convertingterminal hydroxyl groups to esters, such as acid anhydrides (e.g.,acetic anhydride), acid chlorides (acetyl chloride), and/or activeesters (e.g., p-nitrophenyl esters). Other endcap agents include alkyland aryl isocyanates, which form carbamates (urethanes) with terminalhydroxy groups. Other endcap agents include alkylating agents capable offorming alkyl ethers, aromatic ethers including benzyl ethers, silylethers, acetals, ketals, and the like. Still other endcap agents includeperhalogenated (e.g., perfluorinated) derivatives of any of theforegoing endcap agents. In an embodiment, the endcap agent is aceticanhydride, which converts reactive hydroxy end groups to acetate estergroups.

Average Molecular Weight.

The final block polymer preferably has a number average molecular weightMn as determined by size exclusion chromatography of at least 1500g/mol, more specifically 1500 g/mol to 1,000,000 g/mol, 4000 g/mol to150000 g/mol, or 4000 g/mol to 50000 g/mol. In an embodiment, the finalblock polymer has a number average molecular weight Mn of 10,000 to20,000 g/mole. The final block polymer also preferably has a narrowpolydispersity index (PDI), generally from 1.01 to 2.0, moreparticularly 1.01 to 1.30, and even more particularly 1.01 to 1.25.

Layered Structures

Directed polymer self-assembly (DSA) can potentially extend currentlithography by enhancing the spatial resolution and/or controlling thecritical dimension variation of a predefined pattern on a substrate. DSAcan be implemented by graphoepitaxy and/or chemical epitaxy. Ingraphoepitaxy, self-assembly (SA) of a material (e.g., a block polymer)is guided by topographical features of a lithographically pre-patternedsurface and the surface properties of those features. In chemicalepitaxy, self-assembly of a material is guided by lithographicallydefined chemical pre-patterns of a substrate surface.

FIGS. 4A to 4E are cross-sectional layer diagrams illustrating DSA bygraphoepitaxy. Layered structure 10 comprises topographic pre-pattern 11disposed on substrate 12 (FIG. 4A). Substrate 12 can comprise one ormore sub-layers (not shown). Pre-pattern 11 comprises topographicalfeatures 13 disposed on substrate surface 19. Features 13 have sidewalls14, top surface 15, height h′, and width w′. Features 13 are separatedby trench areas 16 having bottom surface 17, which can be a surface ofsubstrate 12 or a sub-layer thereof (not shown). Pre-pattern 11 can beformed by any suitable lithographic technique. Features 13 can compriseany suitable material 18 for directing self-assembly. For example,features 13 can comprise a resist material, which can be a positiveand/or negative tone resist material.

The topography of pre-pattern 11 guides self-assembly of the final blockpolymer, which is allocated in the trench area of features 13. Forgraphoepitaxy, the thickness (i.e., height h′) of features 13 istypically greater than or comparable to the thickness of the blockpolymer undergoing self-assembly. Additionally, the surface propertiesof sidewalls 14 and bottom surface 17 should be suitable for guidingself-assembly of the block polymer. In particular, one domain of theself-assembled final block polymer should have a higher affinity forsidewalls 14 and/or bottom surface 17 compared to a second domain of theself-assembled final block polymer.

A coating mixture comprising the final block polymer, a suitablesolvent, and any optional additives is applied to pre-pattern 11 usingany suitable technique (e.g., spin coating), thereby allocating thefinal block polymer substantially in trench areas 16. Pre-pattern 11 isinsoluble in or substantially insoluble in the solvent used to preparethe coating mixture. Removal of the solvent from the applied coatingmixture provides layered structure 20 comprising layer 21 (FIG. 4B).Layer 21 comprises features 13 and regions of final block polymer 22disposed on bottom surface 27 of trench areas 16.

Final block polymer 22 can self-assemble (phase separate) to formlayered structure 30 comprising self-assembled layer 31 (FIG. 4C).Self-assembly can be spontaneous and/or assisted by a thermally treating(annealing) layer 21. Self-assembled layer 31 comprises first domains32, second domains 33, features 13, and trench areas 16.

One of the domains, for example first domains 32, can be selectivelyremoved (e.g., ion-etched) or modified in the presence of the seconddomains 33, to generate topographical or chemical contrast. Selectiveremoval of one of the domains can also remove underlying orientationcontrol material (not shown), producing layered structure 40 comprisingrelief pattern 41 (FIG. 4D). An orientation control material can be anysuitable material for controlling self-assembly of the final blockpolymer. Relief pattern 41 comprises second domains 33 disposed onbottom surface 42, openings 43, and features 13. Openings 43 can have awidth w″ of about 3 nm to about 100 nm. The selective removal processmay be carried out by a thermal bake (for thermally decomposablematerials), a reactive ion etch process, dissolution in a selectivesolvent, or a combination thereof. A chemical modification may beaccomplished by a variety of known methods. For example, domains may beselectively reacted with silanes or silyl chlorides to introduce siliconcontent into a domain and thereby increase its plasma etch resistance.Alternatively, chemical agents may be used to bind or chemically coupleto functional groups that are exclusively located in one type ofself-assembled domain, to effect, for example, increased solubilityproperty differences that can advantageously be used to selectivelyremove one domain in the presence of the other domain.

Finally, relief pattern 41 can be transferred to substrate 12, therebyforming layered structure 50 comprising patterned region 51 of substrate12 (FIG. 4E). Patterned region 51 can be a pattern of lines, holes,pits, or a chemically altered state of the substrate materialrepresented by areas 52. Patterned region 51 can extend into one or morelayers of substrate 12. The pattern transfer can be accomplished, forexample, by using a reactive ion etch process.

Chemical epitaxy is further illustrated in the process of FIGS. 5A to5D. In FIG. 5A, layered structure 60 is composed of a pre-pattern 61comprising uncovered substrate surfaces 62 and features 63. Features 63have height j′, top surface 68, sidewalls 67 and can comprise anysuitable material 64 disposed on surface 65 of substrate 12. The trencharea 62 has width w and feature 63 have width z. The pitch (w+z) isabout the pitch of the self-assembled material (e.g., block polymer).Pre-pattern 61 is not soluble in a solvent used to form a coatingmixture comprising the final block polymer. In this example pre-pattern61 and substrate surface 66 provide a chemical pre-pattern forself-assembly of the final block polymer. Height j′ of trench 63 issmall enough relative to the thickness of the final block copolymer thatsidewall 67 has negligible influence on self-assembly; that is,self-assembly is controlled primarily by top surface 68 and substratesurface 66. In this case, top surface 68 and substrate surface 66 havedifferent surface wetting properties for the final block polymer.Self-assembly can be directed by top surface 68 or by substrate surface66, or both when each surface has a preferential affinity for adifferent domain of the self-assembled material. In this example, topsurface 68 has a preferential affinity for domain 76 of theself-assembled material (FIG. 4B). The surface properties of photoresisttop surface 68 can be modified to tune the chemical affinity prior toapplication of the SA materials. The height j (i.e., thickness) of thenon-crosslinked, exposed photoresist 62 should be less than thethickness of the SA materials in order to direct self-assembly primarilyby chemical interactions. The properties of substrate surface 66 can bethe same, or substantially the same as, the properties of substratesurface 12.

A solution comprising the final block polymer and a suitable solvent iscast onto pre-pattern 61 without dissolving features 63. Removing of thesolvent and optionally baking and/or annealing of the layer results inlayered structure 70 comprising a domain pattern 71 (FIG. 5B). Domainpattern 71 comprises first domains 72 of self-assembled final blockpolymer, which are disposed on substrate surface 66, and second domains73 of self-assembled final block polymer disposed on top surface 68 offeatures 63 (FIG. 5A). In this example, top surface 68 of features 63has a preferential affinity for domains 73; therefore, domains 73preferentially self-assemble on top surface 68. Additionally, substratesurface 66 can have a preferential affinity for domain 72, but not fordomain 73. Alternatively, substrate 66 can have no preferential affinityfor either domains 72 or 73, but can support the perpendicularorientation of both domains 72 or 73. In such a fashion, pre-pattern 61guides the location of the self-assembled domains of the final blockpolymer.

One of the domains 72 or 73 can be selectively removed in the presenceof the other domain. In this example first domains 72 are selectivelyremoved, producing layered structure 80 comprising relief pattern 81(FIG. 5C). Relief pattern 81 comprises openings 82 that allow a patternto be transferred to substrate 12, producing layered structure 90comprising altered substrate pattern 91 (FIG. 5D). Pattern 91 comprisesaltered substrate regions 92. In this example the width (w) of trencharea 62 plus the width (z) of the feature 63 (FIG. 5A) is about equal tothe pitch of self-assembled material of domain pattern 71 (FIG. 5B),which produces no change in the spatial frequency of the domain patternrelative to the pre-pattern 61.

In general, width z of the feature 63 can be larger or smaller than thewidth of the domain 73 for which it has preferential affinity. The pitchof the chemical pre-pattern (w+z) should be roughly commensurate with anintegral multiple of the pitch of the self-assembled domains of blockpolymers. For guiding self-assembly of a final block polymer, the pitchof the chemical pre-pattern (w+z) should be roughly an integral multipleof the dimensions of the self-assembled domains of the final blockpolymer.

The substrate, and more particularly the surface of the substrate, cancomprise inorganic or organic materials such as metals, carbon, orpolymers. More particularly, the substrate can comprise a semiconductingmaterial including, for example, Si, SiGe, SiGeC, SiC, Ge alloys, GaAs,InAs, InP, as well as other III-V or II-VI compound semiconductors. Thesubstrate can also comprise a layered semiconductor such as Si/SiGe, ora semiconductor-on-insulator (SOI). In particular, the substrate cancontain a Si-containing semiconductor material (i.e., a semiconductormaterial that includes Si). The semiconductor material can be doped,non-doped or contain both doped and non-doped regions therein.

The substrate can have a top anti-reflection control layer (ARC layer)or a bottom ARC layer (BARC layer) to reduce reflectivity of the filmstack. Many suitable BARCs are known in the literature including singlelayer BARCs, dual layer BARCs, graded BARCs, and developable BARCs(DBARCs). The substrate can also comprise a hard mask, a transfer layer(e.g., planarizing layer, spin-on-glass layer, spin-on carbon layer),and other materials as required for the layered device.

The substrate can comprise an orientation control layer. Exemplaryorientation control materials include polymers comprising a hydroxylgroup. These include hydroxyl-terminated polymers (e.g.,hydroxyl-terminated poly(styrene-co-methyl methacrylate and blends ofhydroxyl-terminated poly(styrene), hydroxyl-terminated poly(methylmethacrylate), and poly(styrene-b-methyl methacrylate)),hydroxyl-functionalized polymers (e.g., poly(styrene-co-methylmethacrylate-co-2-hydroxyethyl methacrylate)). Other orientation controlmaterials include materials comprising reactive groups, such as thosederived from epoxydicyclopentadiene methacrylate, glycidyl methacrylate,or vinyl cinnamates. Exemplary materials comprising reactive groupsinclude poly(styrene-co-epoxydicyclopentadiene methacrylate),poly(styrene-co-methyl methacrylate-co-epoxydicyclopentadienemethacrylate), poly(styrene-co-methyl methacrylate-co-glycidylmethacrylate), poly(styrene-co-methyl methacrylate-co-vinyl cinnamate)poly(styrene-co-methyl methacrylate-co-vinyl benzocyclobutane), andpoly(alpha-methyl styrene-co-methyl methacrylate)). The reactivepolymers may react as a result of thermal or photochemical treatmenteither alone or in conjuction with an additional crosslinking agent. Inparticular, a catalytic species such as a strongly acidic species may beused to facilitate reaction. The strongly acidic species may be directlyincorporated into the orientation control material or the solutioncomprising the orientation control material. Alternatively, a thermalacid generator or photoacid generator molecule may be used to generatean acidic species as a result of thermal or photochemical treatment,respectively.

Other non-limiting examples of orientation control materials includematerials used in ARC layers, which can include homopolymers andcopolymers selected from the group consisting of polybisphenols,polysulfones, polycarbonates, polyhydroquinones, polyphthalates,polybenzoates, polyphenylethers, polyhydroquinone alkylates,polycarbamates, polymalonates and mixtures thereof. These moieties aretypically functionalized in order to tune the required physicalproperties of the polymer (optical constants, surface energy). Thepolymer components can also contain a plurality of reactive sitesdistributed along the polymer for reaction with a crosslinkingcomponent. More specific materials used in ARC layers include polymersdisclosed in US Patent Application 20090186294, includingpoly(4,4′-methylenebisphenol-co-epichlorohydrin),poly(4,4′-ethylidenebisphenol-co-epichlorohydrin),poly(4,4′-isopropylidenebisphenol-co-epichlorohydrin),poly(4,4′-isopropylidenebis[2-methylphenol]-co-epichlorohydrin),poly(4,4′-isopropylidenebis[2,6-dimethylphenol]-co-epichlorohydrin),poly(4,4′-cyclohexylidenebisphenol-co-epichlorohydrin),poly(4,4′-[1-phenylethylidene]bisphenol-co-epichlorohydrin),poly(4,4′-trifluoroisopropylidenebisphenol-co-epichlorohydrin),poly(4,4′-hexafluoroisopropylidenebisphenol-co-epichlorohydrin),poly(4,4′-sulfonylbisphenol-co-epichlorohydrin), poly(bisphenol AFadipic ester), poly(bisphenol AF succinic ester),poly(4,4′-hexafluoroisopropylidenediphthalate-co-epichlorohydrin),poly(4,4′-hexafluoroisopropylidenediphthalate-co-poly(bisphenol AF)),poly(4,4′-hexafluoroisopropylidenebisbenzoate-co-epichlorohydrin),poly(3,3′,4,4′-benzophenonetetracarboxylate-co-epichlorohydrin),poly(4,4′-hexafluoroisopropylidenediphthalate-co-epichlorohydrin-co-2,6-bis[hydroxymethyl]-p-cresol),poly(3,3′,4,4′-benzophenonetetracarboxylate-co-epichlorohydrin-co-2,6-bis[hydroxymethyl]-p-cresol),poly(terephthalate-co-epichlorohydrin),poly(2-nitroterephthalate-co-epichlorohydrin),poly(2-nitrophthalate-co-epichlorohydrin),poly(2-nitroisophthalate-co-epichlorohydrin),poly(hydroquinone-co-epichlorohydrin),poly(methylhydroquinone-co-epichlorohydrin),poly(1,2,4-benzenetriol-co-epichlorohydrin),poly(methylene-bis[4-aminophenyl]-co-glycerol carbamate),poly(isopropylidene-bis[4-aminophenyl]-co-glycerol carbamate),poly(isopropylidene-bis[3-carboxy-4-aminophenyl]-co-glycerol carbamate),poly(methylene-bis[4-hydroxyphenyl]-co-glycerol carbonate),poly(isopropylidene-bis[4-hydroxyphenyl]-co-glycerol carbonate),poly(isopropylidene-bis[3-carboxy-4-hydroxyphenyl]-co-glycerolcarbonate), poly(2-phenyl-1,3-propanediol malonate),poly(2-phenyl-1,3-propanediol 2-methyl-malonate), poly(1,3-propanediolbenzylidene-malonate), poly(2-phenyl-1,3-propanediolbenzylidene-malonate), glycidyl endcapped poly(bisphenolA-co-epichlorohydrin), and silicon-containing anti-reflection coatingA940 from Shin Etsu. Another more specific orientation control materialdescribed in U.S. Pat. No. 7,521,090 comprisespoly(styrene-co-epoxydicyclopentadiene methacrylate) random copolymer,P(S-r-EDCPMA):

wherein x and y are each integers greater than 1. Other orientationcontrol materials include poly(styrene-co-methylmethacrylate-co-epoxydicyclopentadiene methacrylate),poly(styrene-co-methyl methacrylate-co-glycidyl methacrylate),poly(styrene-co-methyl methacrylate-co-2-hydroxyethyl methacrylate),poly(styrene-co-methyl methacrylate-co-4-vinyl cinammate),poly(styrene-co-methyl methacrylate-co-vinyl benzocyclobutane),poly(styrene-co vinyl benzocyclobutane, poly(alpha-methylstyrene-co-methyl methacrylate), and poly(methyl glutarimide) (PMGI).Other orientation control materials comprise polymer brush layersincluding those formed by hydroxyl-terminated poly(styrene-co-methylmethacrylate), poly(styrene-co-methyl methacrylate-co-2-hydroxyethylmethacrylate), hydroxyl-terminated poly(styrene), hydroxyl-terminatedpoly(methyl methacrylate), poly(styrene-b-methyl methacrylate) blockcopolymer, and combinations of the foregoing surface affinity materials.Other orientation control materials include self-assembled monolayers.

The following examples illustrate the methods of forming the final blockpolymers and layered structures that utilize the self-assemblyproperties of the final block polymers.

EXAMPLES

Materials used in the following examples are listed in Table 6.

TABLE 6 ABBREVIATION DESCRIPTION SUPPLIER DBU1,8-Diazabicyclo[5,4,0]undec-7- Sigma Aldrich ene BisMPADimethylolpropinoic acid Perstorp BnOH Benzyl alcohol Sigma Aldrich DCMDichloromethane Sigma Aldrich AcCl Acetyl Chloride Sigma Aldrich TEATriethylamine Sigma Aldrich BriBr α-Bromoisobutyryl bromide SigmaAldrich THF Tetrahydrofuran Sigma Aldrich MeOH Methanol Sigma AldrichACN Acetonitrile Sigma Aldrich Sty Styrene Sigma Aldrich GMA Glycidylmethacrylate Sigma Aldrich ACN Acrylonitrile Sigma Aldrich Ethylchloroformate Sigma Aldrich EtAc Ethyl acetate Sigma Aldrich Tol TolueneSigma Aldrich DPP Diphenyl phosphate, MW 250.2 Sigma Aldrich AIBNAzobisisobutyronitrile Sigma Aldrich EG Ethylene glycol Sigma AldrichPS-OH Hydroxyl-end-functional AZ Electronic polystyrene; Mn = 6200Materials Mn = 10000 P2O5 Phosphorus pentaoxide Aldrich TMC Trimethylenecarbonate Richman Chemicals CuBr Copper (I) bromide Sigma Aldrich PMDETAN,N,N′,N′,N″- Sigma Aldrich pentamethyldiethylenetriamine AnisoleAnisole Sigma Aldrich Si Gel Silica Gel Sigma Aldrich

Herein, Mn is the number average molecular weight, Mw is the weightaverage molecular weight, and MW is the molecular weight of onemolecule.

All solvents were of analytical grade, and used as received. Beforetransferring into the glove box, monomers and other reagents (e.g.,initiator, monomer, etc.) were dried extensively by freeze-drying underhigh vacuum.

ATRP initiator, 2-hydroxyethyl 2-bromo-2-methylpropanoate,

was prepared as previously reported (C. Koulic et al., Polymer, 2001,42, 7, 2947).

Methyl carbonate (MTC-Me) monomer:

was prepared as previously reported (Y. Zoul et al., Polymer, 45(16),5459-5463; 2004).

Example 1 Synthesis of P-1 Homopolymer Using DBU Catalyst

To an oven dried 4 ml glass vial equipped with a magnetic stir bar,as-purchased TMC (0.3 g, 2.94 mmol), benzyl alcohol (BnOH, 5.29 mg,0.049 mmol), and DCM (0.4 ml) were added. The reaction mixture wasstirred until TMC was completely dissolved in DCM, upon which DBU (22mg, 0.147 mmol) was added. The reaction mixture was stirred at roomtemperature for 85 minutes in a glove box. The reaction was stopped bybringing the reaction vial out of the glove box and by adding acetylchloride (30 mg, 0.384 mmol) and further stirring the reaction mixturefor 45 minutes at room temperature. The polymer was precipitated in coldmethanol (0° C.). Methanol was decanted and the polymer was dried in avacuum oven at room temperature. The dried polymer was further purifiedby dissolving in THF and reprecipitating in cold methanol (0° C.).Methanol was decanted and the polymer was dried in a vacuum oven at roomtemperature to obtain the final product. Mn=6.5 k, Mw=7.2 k, PDI=1.10,n=62.

Example 2 Synthesis of P-2 Homopolymer Using DPP Catalyst

To an oven dried 4 ml glass vial equipped with a magnetic stir bar,as-purchased TMC (0.278 g, 2.72 mmol), benzyl alcohol (2.94 mg, 0.027mmol), and DCM (0.46 ml) were added. The reaction mixture was stirreduntil a TMC was completely dissolved in DCM, upon which DPP (68 mg, 272mmol) was added. The reaction mixture was stirred at room temperaturefor 2.5 hours in a glove box. The reaction was stopped by bringing thereaction vial out of the glove box and by adding TEA (27 mg, 0.272 mmol)and further stirring the reaction mixture for 45 minutes at roomtemperature. The polymer was precipitated in cold methanol (0° C.).Methanol was decanted and the polymer was dried in a vacuum oven at roomtemperature. The dried polymer was further purified by dissolving in THFand reprecipitating in cold methanol (0° C.). Methanol was decanted andthe polymer was dried in a vacuum oven at room temperature to obtain thefinal product. Mn=2.98 k, Mw=3.1 k, PDI=1.06, n=28.

Example 3

Recrystallization of TMC monomer from ethyl acetate. To a 100 ml roundbottom flask equipped with a magnetic stir bar, TMC (10.0 g, 98 mmol)and ethyl acetate (10 ml) were added. The reaction mixture was heated inan oil-bath at 40° C. until the TMC completely dissolved in ethylacetate to form a clear mixture. At this point, the heating was stoppedand the TMC was allowed to crystallize from ethyl acetate. TMC wasisolated in a frit funnel by removing ethyl acetate under vacuum. TheTMC was dried at room temperature under vacuum for one day. Theresulting TMC monomer was further dried using Abderhalden's dryingpistol apparatus with phosphorus pentoxide in the trap to collectresidual moisture. FIG. 6 is a proton NMR spectrum of the TMC afterdrying with Abderhalden's drying apparatus.

Example 4

Recrystallization of TMC monomer from toluene. To a 100 ml round bottomflask equipped with a magnetic stir bar, TMC (10.0 g, 98 mmol) andtoluene (10 ml) were added. The reaction mixture was heated in anoil-bath at 40° C. until the TMC completely dissolved in toluene to forma clear mixture. At this point, the heating was stopped and the TMC wasallowed to crystallize from toluene. TMC was isolated in a frit funnelby removing the toluene under vacuum. The TMC was dried at roomtemperature under vacuum for two days. This process was repeated for twomore times and the resulting triple crystallized TMC monomer was driedunder high vacuum for two days followed by drying in a desiccatorequipped with calcium sulfate desiccant. FIG. 7 is a proton NMR spectrumof the TMC after three recrystallization cycles.

Example 5 Synthesis of P-2 Homopolymer Using DPP Catalyst Using TMC fromExample 4

To an oven dried 4 ml glass vial equipped with a magnetic stir bar, TMC(50 mg, 0.49 mmol) from Example 4, benzyl alcohol (0.5 mg, 0.0049 mmol),and DCM (0.12 ml) were added. The reaction mixture was stirred until aTMC was completely dissolved in DCM, upon which DPP (12 mg, 0.049 mmol)was added. The reaction mixture was stirred at room temperature for 3.75hours in a glove box. The reaction was stopped by bringing the reactionvial out of the glove box and by adding TEA (27 mg, 0.272 mmol) andfurther stirring the reaction mixture for 45 minutes at roomtemperature. The polymer P-2 was not isolated. Mn=3.4 k, Mw=3.65 k,PDI=1.06, n=32.

Example 6 Synthesis of P-3 Homopolymer with DPP Catalyst Using TMC fromExample 4 without Initiator

In this instance, it is postulated that DPP acts as both catalyst andinitiator for the ring opening polymerization. To an oven dried 4 mlglass vial equipped with a magnetic stir bar, TMC (100 mg, 98 mmol) fromExample 4 and DCM (0.24 ml) were added. The reaction mixture was stirreduntil the TMC was completely dissolved in DCM, upon which DPP (16 mg,0.064 mmol) was added. The reaction mixture was stirred at roomtemperature for 22 hours in a glove box. The reaction was stopped bybringing the reaction vial out of the glove box and by adding TEA (27mg, 0.272 mmol) and further stirring the reaction mixture for 45 minutesat room temperature. The polymer was not isolated. Mn=18.0 k, Mw=21.3 k,PDI=1.18, n=171.

Example 7

Synthesis of P-3 homopolymer with DPP catalyst using TMC from Example 4without initiator. The structure of P-3 is shown in Example 6. To anoven dried 4 ml glass vial equipped with a magnetic stir bar, TMC (100mg, 98 mmol) from Example 4 and DCM (0.24 ml) were added. The reactionmixture was stirred until a TMC was completely dissolved in DCM, uponwhich DPP (8 mg, 0.032 mmol) was added. The reaction mixture was stirredat room temperature for 22 hours in a glove box. The reaction wasstopped by bringing the reaction vial out of the glove box and by addingTEA (27 mg, 0.272 mmol) and further stirring the reaction mixture for 45minutes at room temperature. The polymer was not isolated. Mn=22.4 k,Mw=24.8 k, PDI=1.10, n=213.

Table 7 summarizes the preparations of TMC homopolymers.

TABLE 7 Time Example Monomer Catalyst Initiator Temp (hours) Polymer nMn Mw PDI 1 TMC DBU BnOH r.t. 1.4 P-1 62 6.5 7.2 1.1 2 TMC DPP BnOH r.t.2.5 P-1 28 2.98 3.1 1.06 5 TMC-4 DPP BnOH r.t. 3.75 P-2 32 3.4 3.65 1.066 TMC-4 DPP r.t. 22 P-3 171 18 21.3 1.18 7 TMC-4 DPP r.t. 22 P-3 21322.4 24.8 1.1

Synthesis of PS—OH by ATRP Example 8 Synthesis of Hydroxyl-EndFunctional Polystyrene, PS—OH, by ATRP, Mn=9.4 k

To a 100 ml Schlenk flask equipped with a stir bar, styrene (29.9 g,0.28 mol), 2-hydroxyethyl 2-bromo-2-methylpropanoate (0.10 g, 0.473mmol, MW=211, ATRP initiator), and CuBr (68 mg, 0.473 mmol) were added.The flask was sealed with a rubber septum and was purged by bubblingnitrogen for one hour. At this point, PMDETA (82 mg, 0.473 mmol) wasadded and the reaction flask was placed in an oil-bath set at 110° C.for 75 minutes. The reaction was stopped by placing the Schlenk flask inan ice-water bath. The flask was opened to air at which time thereaction mixture turned dark green. The mixture was diluted by addingTHF (100 ml) and was passed through a short silica-gel column to removecopper catalyst. The resulting solution was concentrated under vacuumand was precipitated twice in methanol from THF. The polymer wascollected in a frit funnel and was dried under vacuum for 24 hours at50° C. Mn=9.4 k, Mw=10.5 k, PDI=1.12, n=85.

Example 9

Synthesis of PS—OH by ATRP, Mn=5.5 k. The structure of PS—OH is shown inExample 8. To a 100 ml Schlenk flask equipped with a stir bar, styrene(14.80 g, 0.142 mol), 2-hydroxyethyl 2-bromo-2-methylpropanoate (0.20 g,0.946 mmol, ATRP initiator), CuBr (0.126 g, 0.946 mmol) and anisole (15g) were added. The flask was sealed with a rubber septum and was purgedby bubbling nitrogen for one hour. At this point, PMDETA (0.168 g, 0.946mmol) was added and the reaction flask was placed in an oil-bath set at110° C. for 280 minutes. The reaction was stopped by placing the Schlenkflask in an ice-water bath. The flask was opened to air at which timethe reaction mixture turned dark green. The mixture was diluted byadding THF (100 ml) and was passed through a short silica-gel column toremove copper catalyst. The resulting solution was concentrated undervacuum and was precipitated twice in methanol from THF. The polymer wascollected in a frit funnel and was dried under vacuum for 24 hours at50° C. Mn=5.5 k, Mw=6.0 k, PDI=1.07, n=49.

Example 10

Synthesis of PS—OH by ATRP Mn=6.6 k. The structure of PS—OH is shown inExample 8. To a 100 ml Schlenk flask equipped with a stir bar, styrene(14.80 g, 0.142 mol), 2-hydroxyethyl 2-bromo-2-methylpropanoate (0.20 g,0.946 mmol, ATRP initiator), CuBr (0.126 g, 0.946 mmol) and anisole (15g) were added. The flask was sealed with a rubber septum and was purgedby bubbling nitrogen for one hour. At this point, PMDETA (0.168 g, 0.946mmol) was added and the reaction flask was placed in an oil-bath set at110° C. for 310 minutes. The reaction was stopped by placing the Schlenkflask in an ice-water bath. The flask was opened to air at which timethe reaction mixture turned dark green. The mixture was diluted byadding THF (100 ml) and was passed through a short silica-gel column toremove copper catalyst. The resulting solution was concentrated undervacuum and was precipitated twice in methanol from THF. The polymer wascollected in a frit funnel and was dried under vacuum for 24 hours at50° C. Mn=6.5 k, Mw=7.0 k, PDI=1.07, n=58.

Table 8 summarizes the preparations of PS—OH by ATRP.

TABLE 8 Time Example Monomer Catalyst Initiator Temp (hours) Polymer nMn Mw PDI 8 Styrene CuBr/PMDETA HEBMP 110 1.25 PS-OH 85 9.4 10.5 1.12 9Styrene CuBr/PMDETA HEBMP 110 4.7 PS-OH 49 5.5 6 1.07 10 StyreneCuBr/PMDETA HEBMP 110 5.2 PS-OH 58 6.5 6 1.07

Synthesis of Polystyrene-b-Polycarbonate Block Copolymers

Examples 11-16 form block copolymer PS-b-PTMC by the following reactionscheme.

In the following examples PS refers to polystyrene block and PTMC refersto poly(trimethylene carbonate) block in the formula PS-b-PTMC. Thenumber average molecular weight of each block is shown in parentheses(e.g., in PS(5.5 k)-b-PTMC(4.8 k), the PS block has an Mn=5500 (n=51),and the PTMC block has an Mn=4800 (m=46).

Example 11

Synthesis of PS-b-PTMC with DBU catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, PS—OH (0.15 g, 0.0272 mmol,initiator, from Example 9), TMC (0.152 g, 1.49 mmol, from Example 4),and DCM (0.37 ml) were added. The reaction mixture was stirred until thePS—OH macroinitiator and TMC were completely dissolved in DCM, uponwhich DBU (12 mg, 0.078 mmol) was added. The reaction mixture wasstirred at room temperature for 150 minutes in a glove box. The reactionwas stopped by bringing the reaction vial out of the glove box and byadding DCM (1 ml), TEA (0.27 g, 02.72 mmol) and acetyl chloride (about21 mg, 0.272 mmol). The reaction was further stirred for two hours atroom temperature. The resulting polymer was isolated by precipitatingthe reaction mixture in methanol. The product was collected in a fritfunnel by removing methanol under vacuum and the resulting solids wereredissolved in THF to form a 20 wt % solution and reprecipitated inmethanol. The solids were collected in a frit funnel and dried undervacuum at 40° C. for two hours to obtain the resulting compound. Mn(GPC)=13.1 k, Mw=14.3 k, PDI=1.09; Mn (NMR)=PS(5.5 k)-b-PTMC(4.8 k),n=51, m=46; TMC % conversion: about 86%.

Example 12

Synthesis of PS-b-PTMC with DBU catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, PS—OH (0.5 g, 0.077 mmol, fromExample 10), TMC (0.35 g, 3.43 mmol, from Example 3), and DCM (0.75 ml)were added. The reaction mixture was stirred until the PS—OHmacroinitiator and TMC were completely dissolved in DCM, upon which DBU(58 mg, 0.376 mmol) was added. The reaction mixture was stirred at roomtemperature for four hours in a glove box. The reaction was stopped bybringing the reaction vial out of the glove box and by adding acetylchloride (about 32 mg, 0.4 mmol) and TEA (10 mg, 0.1 mmol). The reactionwas further stirred for two hours at room temperature. The resultingpolymer was isolated by precipitating the reaction mixture in methanol.The product was collected in a frit funnel by removing methanol undervacuum and the resulting solids were redissolved in THF to form a 20 wt% solution and reprecipitated in methanol. The solids were collected ina frit funnel and dried under vacuum at 40° C. for two hours to obtainthe resulting compound. Mn (GPC)=13.5 k, Mw=15.6 k, PDI=1.15; Mn(NMR)=PS(6.5 k)-b-PTMC(4.5 k), n=60, m=43; TMC % conversion was about98%. FIG. 8 is GPC trace of this sample.

Example 13

Synthesis of PS-b-PTMC with DPP catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, PS—OH (40 mg, 0.004 mmol, fromExample 8), TMC (51 mg, 0.5 mmol, from Example 3), and DCM (0.12 ml)were added. The reaction mixture was stirred until the PS—OHmacroinitiator and TMC were completely dissolved in DCM, upon which DPP(10 mg, 0.04 mmol) was added. The reaction mixture was stirred at roomtemperature for 15 hours in a glove box. The reaction was stopped bybringing the reaction vial out of the glove box and by adding DCM (0.3ml), TEA (40 mg, 0.4 mmol), and acetyl chloride (about 10 mg, 0.128mmol). The reaction was further stirred for two hours at roomtemperature. The resulting polymer was isolated by precipitating thereaction mixture in methanol. The product was collected in a frit funnelby removing methanol under vacuum and the resulting solids wereredissolved in THF to form a 20 wt % solution and reprecipitated inmethanol. The solids were collected in a frit funnel and dried undervacuum at 40° C. for two hours to obtain the resulting compound. Mn(GPC)=17.9 k, Mw=20.1 k, PDI=1.12; Mn (NMR)=PS(9.4 k)-b-PTMC(11.5 k),n=87, m=112; TMC % conversion: about 94%. FIG. 9 is GPC trace of thissample.

Example 14

Synthesis of PS-b-PTMC with DPP catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, PS—OH (0.15 g, 0.0272 mmol, fromExample 9), TMC (0.138 g, 1.36 mmol, from Example 4), and DCM (0.34 ml)were added. The reaction mixture was stirred until the PS—OHmacroinitiator and TMC were completely dissolved in DCM, upon which DPP(68 mg, 0.272 mmol) was added. The reaction mixture was stirred at roomtemperature for 20 hours in a glove box. The reaction was stopped bybringing the reaction vial out of the glove box and by adding DCM (1ml), TEA (0.27 g, 02.72 mmol) and acetyl chloride (about 21 mg, 0.272mmol). The reaction was further stirred for two hours at roomtemperature. The resulting polymer was isolated by precipitating thereaction mixture in methanol. The product was collected in a frit funnelby removing methanol under vacuum and the resulting solids wereredissolved in THF to form a 20 wt % solution and reprecipitated inmethanol. The solids were collected in a frit funnel and dried undervacuum at 40° C. for two hours to obtain the resulting compound. Mn(GPC)=11.9 k, Mw=12.9 k, PDI=1.07; Mn (NMR)=PS(5.5 k)-b-PTMC(5.4 k),n=51, m=52; TMC % conversion: >99%.

Example 15

Synthesis of PS-b-PTMC with DPP catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, PS—OH (0.15 g, 0.0272 mmol, fromExample 9), TMC (0.167 g, 1.68 mmol, from Example 4), and DCM (0.40 ml)were added. The reaction mixture was stirred until the PS—OHmacroinitiator and TMC were completely dissolved in DCM, upon which 68mg (0.272 mmol) of DPP was added. The reaction mixture was stirred atroom temperature for 20 hours in a glove box. The reaction was stoppedby bringing the reaction vial out of the glove box and by adding 1 ml ofDCM, 0.27 g (02.72 mmol) of TEA and ˜21 mg (0.272 mmol) of acetylchloride. The reaction was further stirred for two hours at roomtemperature. The resulting polymer was isolated by precipitating thereaction mixture in methanol. The product was collected in a frit funnelby removing methanol under vacuum and the resulting solids wereredissolved in THF to form a 20 wt % solution and reprecipitated inmethanol. The solids were collected in a frit funnel and dried undervacuum at 40° C. for two hours to obtain the resulting compound. Mn(GPC)=16.1 k, Mw=17.5 k, PDI=1.08. Mn (NMR)=PS(5.5 k)-b-PTMC(6.3 k),n=51, m=62; TMC % conversion >99%

Example 16

Synthesis of PS-b-PTMC with DPP catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, PS—OH (0.15 g, 0.0272 mmol, fromExample 9), TMC (0.194 g, 1.90 mmol, from Example 4), and DCM (0.47 ml)were added. The reaction mixture was stirred until the PS—OHmacroinitiator and TMC were completely dissolved in DCM, upon which DPP(68 mg, 0.272 mmol) was added. The reaction mixture was stirred at roomtemperature for 20 hours in a glove box. The reaction was stopped bybringing the reaction vial out of the glove box and by adding DCM (1ml), TEA (0.27 g, 02.72 mmol) and acetyl chloride (about 21 mg, 0.272mmol). The reaction was further stirred for two hours at roomtemperature. The resulting polymer was isolated by precipitating thereaction mixture in methanol. The product was collected in a frit funnelby removing methanol under vacuum and the resulting solids wereredissolved in THF to form a 20 wt % solution and reprecipitated inmethanol. The solids were collected in a frit funnel and dried undervacuum at 40° C. for two hours to obtain the resulting compound. Mn(GPC)=18.5 k, Mw=20.0 k, PDI=1.08; Mn (NMR)=PS(5.5 k)-b-PTMC(7.7 k),n=51, m=75; TMC % conversion: >99%.

Examples 17-22 form block copolymer by the following reaction schemeusing a polystyrene macroinitiator AZ-PS—OH purchased from AZ ElectronicMaterials. The block copolymers are referred to by the name AZPS-b-PTMCblock copolymers.

Example 17

Synthesis of AZPS-b-PTMC with DPP catalyst. To an oven dried 25 ml roundbottom flask equipped with a magnetic stir bar, AZ-PS—OH (1.00 g, 0.161mmol, Mn=6200, PDI=1.02, obtained from AZ-Electronic Materials,Branchburg, N.J.), TMC (1.217 g, 11.93 mmol, from Example 4), and DCM(2.94 ml) were added. The reaction mixture was stirred until theAZ-PS—OH macroinitiator and TMC were completely dissolved in DCM, uponwhich DPP (800 mg, 3.2 mmol) was added. The reaction mixture was stirredat room temperature for 16 hours in a glove box. The reaction flask wasbrought out of the glove box and cooled at 0° C. by immersing it in anice-water bath. The reaction was stopped by adding DCM (6 ml), TEA (0.7ml, 02.72 mmol) and acetyl chloride (0.25 ml, 3.52 mmol). The reactionwas further stirred for two hours at room temperature. The resultingpolymer was isolated by precipitating the reaction mixture in methanol.The product was collected in a frit funnel by removing methanol undervacuum and the resulting solids were redissolved in THF to form a 20 wt% solution and reprecipitated in methanol. The solids were collected ina frit funnel and dried under vacuum at 40° C. for two hours to obtainthe resulting compound. Mn (GPC)=13.3 k, Mw=13.7 k, PDI=1.029; Mn(NMR)=AZPS(6.2 k)-b-PTMC(7.7 k), n=57, m=75; TMC % conversion: >99%.

Example 18

Synthesis of AZPS-b-PTMC with DPP catalyst. To an oven dried 25 ml roundbottom flask equipped with a magnetic stir bar, AZ-PS—OH (1.00 g, 0.161mmol, Mn=6200, PDI=1.02, obtained from AZ-Electronic Materials,Branchburg, N.J.), TMC (1.217 g, 11.93 mmol, from Example 4), and DCM(2.94 ml) were added. The reaction mixture was stirred until theAZ-PS—OH macroinitiator and TMC were completely dissolved in DCM, uponwhich DPP (400 mg, 1.6 mmol) was added. The reaction mixture was stirredat room temperature for 16 hours in a glove box. The reaction flask wasbrought out of the glove box and cooled at 0° C. by immersing it in anice-water bath. The reaction was stopped by adding DCM (6 ml), TEA (0.7ml, 02.72 mmol) and of acetyl chloride (0.25 ml, 3.52 mmol). Thereaction was further stirred for two hours at room temperature. Theresulting polymer was isolated by precipitating the reaction mixture inmethanol. The product was collected in a frit funnel by removingmethanol under vacuum and the resulting solids were redissolved in THFto form a 20 wt % solution and reprecipitated in methanol. The solidswere collected in a frit funnel and dried under vacuum at 40° C. for twohours to obtain the resulting compound. Mn (GPC)=14.1 k, Mw=14.5 k,PDI=1.029; Mn (NMR)=AZPS(6.2 k)-b-PTMC(7.7 k), n=57, m=75; TMC %conversion >99%.

Example 19

Synthesis of AZPS-b-PTMC with DPP catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, AZ-PS—OH (0.2 g, 0.0322 mmol,Mn=6200, PDI=1.02, obtained from AZ-Electronic Materials, Branchburg,N.J.), TMC (0.242 g, 2.37 mmol, from Example 4), and DCM (0.6 ml) wereadded. The reaction mixture was stirred until the AZ-PS—OHmacroinitiator and TMC were completely dissolved in DCM, upon which DPP(80 mg, 0.32 mmol) was added. The reaction mixture was stirred at roomtemperature for 12 hours in a glove box. Kinetics of TMC ring openingwas monitored by taking aliquots every two hours. The polymer was notisolated.

Example 20

Synthesis of AZPS-b-PTMC with DPP catalyst. To an oven dried 20 ml roundbottom flask equipped with a magnetic stir bar, AZ-PS—OH (0.70 g, 0.113mmol, Mn=6200, PDI=1.02, obtained from AZ-Electronic Materials,Branchburg, N.J.), TMC (1.76 g, 17.25 mmol, from Example 4), and DCM(2.94 ml) were added. The reaction mixture was stirred until theAZ-PS—OH macroinitiator and TMC were completely dissolved in DCM, uponwhich DPP (400 mg, 1.6 mmol) was added. The reaction mixture was stirredat room temperature for 16 hours in a glove box. The reaction flask wasbrought out of the glove box and cooled at 0° C. by immersing it in anice-water bath. The reaction was stopped by adding DCM (6 ml), TEA (0.7ml, 02.72 mmol) and acetyl chloride (0.25 ml, 3.52 mmol). The reactionwas further stirred for two hours at room temperature. The resultingpolymer was isolated by precipitating the reaction mixture in methanol.The product was collected in a frit funnel by removing methanol undervacuum and the resulting solids were redissolved in THF to form a 20 wt% solution and reprecipitated in methanol. The solid was collected in afrit funnel and dried under vacuum at 40° C. for two hours to obtain theresulting compound. Mn (GPC)=14.1 k, Mw=14.5 k, PDI=1.029; Mn(NMR)=AZPS(6.2 k)-PMTC(7.7 k), n=57.4, m=75; TMC % conversion: about50%. FIG. 10 is a graph of the GPC trace.

Example 21

Synthesis of AZPS-b-PTMC with DPP catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, AZ-PS—OH (0.25 g, 0.040 mmol,Mn=6200, PDI=1.02, obtained from AZ-Electronic Materials, Branchburg,N.J.), TMC (0.271 g, 2.66 mmol, from Example 4), and DCM (0.67 ml) wereadded. The reaction mixture was stirred until the AZ-PS—OHmacroinitiator and TMC were completely dissolved in DCM, upon which DPP(100 mg, 0.4 mmol) was added. The reaction mixture was stirred at roomtemperature for 5 hours in a glove box. The reaction was stopped bybringing the reaction vial out of the glove box and by adding DCM (1ml), TEA (0.27 g, 2.72 mmol) and acetyl chloride (about 21 mg, 0.272mmol). The reaction was further stirred for two hours at roomtemperature. The resulting polymer was isolated by precipitating thereaction mixture in methanol. The product was collected in a frit funnelby removing methanol under vacuum and the resulting solids wereredissolved in THF to form a 20 wt % solution and reprecipitated inmethanol. The solids were collected in a frit funnel and dried undervacuum at 40° C. for two hours to obtain the resulting compound. Mn(GPC)=10.5 k, Mw=10.8 k, PDI=1.03; Mn (NMR)=AZPS(6.2 k)-PTMC(3.0 k),n=57, m=29; TMC % conversion: about 50%.

Example 22

Synthesis of AZPS-b-PTMC with DPP catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, AZ-PS—OH (0.20 g, 0.02 mmol,Mn=10000, PDI=1.04, obtained from AZ-Electronic Materials, Branchburg,N.J.), TMC (0.518 g, 5.08 mmol, from Example 4), and DCM (1.27 ml) wereadded. The reaction mixture was stirred until the AZ-PS—OHmacroinitiator and TMC were completely dissolved in DCM, upon which DPP(63 mg, 0.252 mmol) was added. The reaction mixture was stirred at roomtemperature for 21 hours in a glove box. The reaction was stopped bybringing the reaction vial out of the glove box and by adding DCM (1.5ml), TEA (0.27 g, 2.72 mmol) and acetyl chloride (about 21 mg, 0.272mmol). The reaction was further stirred for two hours at roomtemperature. The resulting polymer was isolated by precipitating thereaction mixture in methanol. The product was collected in a frit funnelby removing methanol under vacuum and the resulting solids wereredissolved in THF to form a 20 wt % solution and reprecipitated inmethanol. The solids were collected in a frit funnel and dried undervacuum at 40° C. for two hours to obtain the resulting compound. Mn(GPC)=25 k, Mw=26 k, PDI=1.04; Mn (NMR)=AZPS(10 k)-PTMC(13.0 k), n=92,m=127; TMC % conversion: about 53%.

Fractionation of Block Copolymers Example 23

Fractionation of PS-b-PTMC obtained from Example 12. PS-b-PTMC (30 mg)from Example 12 was dissolved in THF to form a 20 wt % solution and thepolymer was precipitated in methanol:acetonitrile (10 ml, 80:20 volumeratio (v/v)). The precipitated solids and the solvents were collected ina centrifuge tube and the solids was collected by centrifuging at 4000RPM at 0° C. followed by decanting the solvent and drying the solid in avacuum oven at 40° C. for two hours. Mn (GPC)=13.2 k, Mw=15.2 k,PDI=1.15; Mn (NMR)=PS(6.5 k)-b-PTMC(4.4 k). FIG. 11 is a GPC trace ofthis sample (compare with FIG. 8).

Example 24

Fractionation of PS-b-PTMC obtained from Example 12. PS-b-PTMC (30 mg)from Example 12 was dissolved in THF to form a 20 wt % solution and thepolymer was precipitated in methanol:acetonitrile (10 ml, 60:40 v/v).The precipitated solids and the solvents were collected in a centrifugetube and the solids were collected by centrifuging at 4000 RPM at 0° C.followed by decanting the solvent and drying the solids in a vacuum ovenat 40° C. for two hours. Mn (GPC)=13.2 k, Mw=15.4 k, PDI=1.16; Mn(NMR)=PS(6.5 k)-b-PTMC(4.0 k), n=60, m=39. FIG. 12 is a GPC trace ofthis sample (compare with FIG. 8).

Example 25

Fractionation of PS-b-PTMC obtained from Example 12. PS-b-PTMC (30 mg)from Example 12 was dissolved in THF to form a 20 wt % solution and thepolymer was precipitated in methanol:acetonitrile (10 ml, 40:60 v/v).The precipitated solids and the solvents were collected in a centrifugetube and the solids were collected by centrifuging at 4000 RPM at 0° C.followed by decanting the solvent and drying the solids in a vacuum ovenat 40° C. for two hours. Mn (GPC)=14.2 k, Mw=16.3 k, PDI=1.14. Mn(NMR)=PS(6.5 k)-b-PTMC(3.6 k), n=60, m=35. FIG. 13 is a GPC trace ofthis sample (compare with FIG. 8).

Example 26

Fractionation of PS-b-PTMC obtained from Example 13. PS-b-PTMC (30 mg)from Example 13 was dissolved in THF to form a 20 wt % solution and thepolymer was precipitated in methanol:acetonitrile (10 ml, 40:60 v/v).The precipitated solids and the solvents were collected in a centrifugetube and the solids were collected by centrifuging at 4000 RPM at 0° C.followed by decanting the solvent and drying the solids in a vacuum ovenat 40° C. for two hours. Mn (GPC)=18.5 k, Mw=20.0 k, PDI=1.08; Mn(NMR)=PS(9.4 k)-b-PTMC(4.4 k), n=87, m=43. FIG. 14 is a GPC trace ofthis sample.

Example 27

Evaluation of decanted solvent from Example 26. Decanted solvent fromExample 26 was evaporated under vacuum and the resulting solids wereevaluated by GPC and NMR. Mn (GPC)=15.0 k, Mw=15.8K, PDI=1.05; molarratio of Styrene:TMC by NMR=1:22.7.

Example 28

Fractionation of PS-b-PTMC obtained from Example 14. PS-b-PTMC (0.2 g)from Example 14 was dissolved in THF to form a 20 wt % solution and thepolymer was precipitated in methanol:acetonitrile (200 ml, 40:60 v/v).The precipitated solids and the solvents were collected in a centrifugetube and the solids were collected by centrifuging at 4000 RPM at 0° C.followed by decanting the solvent and drying the solids in a vacuum ovenat 40° C. for two hours. Mn (GPC)=11.2 k, Mw=12.1 k, PDI=1.08; Mn(NMR)=PS(5.5 k)-b-PTMC(4.5 k), n=51, m=44.

Example 29

Fractionation of PS-b-PTMC obtained from Example 15. PS-b-PTMC (0.2 g)from Example 15 was dissolved in THF to form a 20 wt % solution and thepolymer was precipitated in methanol:acetonitrile (200 ml, 40:60 v/v).The precipitated solids and the solvents were collected in a centrifugetube and the solids were collected by centrifuging at 4000 RPM at 0° C.followed by decanting the solvent and drying the solids in a vacuum ovenat 40° C. for two hours. Mn (GPC)=14.8 k, Mw=16.1 k, PDI=1.08; Mn(NMR)=PS(5.5 k)-b-PTMC(5.3 k), n=51, m=52.

Example 30

Fractionation of PS-b-PTMC obtained from Example 16. PS-b-PTMC (0.2 g)from Example 16 was dissolved in THF to form a 20 wt % solution and thepolymer was precipitated in methanol:acetonitrile (200 ml, 40:60 v/v).The precipitated solids and the solvents were collected in a centrifugetube and the solids were collected by centrifuging at 4000 RPM at 0° C.followed by decanting the solvent and drying the solids in a vacuum ovenat 40° C. for two hours. Mn (GPC)=17.8 k, Mw=19.3 k, PDI=1.08. Mn(NMR)=PS(5.5 k)-b-PTMC(6.5 k), n=51, m=64.

Example 31

Fractionation of AZPS-b-PTMC obtained from Example 17. AZPS-b-PTMC (0.3g) from Example 17) was dissolved in THF to form a 20 wt % solution andthe polymer was precipitated in methanol:acetonitrile (300 ml, 60:40v/v). The precipitated solids and the solvents were collected in acentrifuge tube and the solids were collected by centrifuging at 4000RPM at 0° C. followed by decanting the solvent and drying the solids ina vacuum oven at 40° C. for two hours. Mn (GPC)=13.5 k, Mw=13.9 k,PDI=1.02; Mn (NMR)=AZPS(6.2 k)-b-PTMC(5.8 k), n=57, m=57.

Example 32

Fractionation of AZPS-b-PTMC obtained from Example 18. AZPS-b-PTMC (0.2g) from Example 18 was dissolved in THF to form a 20 wt % solution andthe polymer was precipitated in methanol:acetonitrile (200 ml, 60:40v/v). The precipitated solids and the solvents were collected in acentrifuge tube and the solids were collected by centrifuging at 4000RPM at 0° C. followed by decanting the solvent and drying the solids ina vacuum oven at 40° C. for two hours. Mn (GPC)=14.0 k, Mw=14.4 k,PDI=1.03; Mn (NMR)=AZPS(6.2 k)-b-PTMC(6.4 k), n=57, m=63.

Example 33

Fractionation of AZPS-b-PTMC obtained from Example 20. AZPS-b-PTMC (0.2g) from Example 20 was dissolved in THF to form a 20 wt % solution andthe polymer was precipitated in methanol:acetonitrile (200 ml, 60:40v/v). The precipitated solids and the solvents were collected in acentrifuge tube and the solids were collected by centrifuging at 4000RPM at 0° C. followed by decanting the solvent and drying the solids ina vacuum oven at 40° C. for two hours. Mn (GPC)=17.2 k, Mw=17.6 k,PDI=1.02; Mn (NMR)=AZPS(6.2 k)-b-PTMC(7.7 k), n=57, m=75. FIG. 15 is aGPC trace of this sample (compare with FIG. 10)

Example 34

Fractionation of AZPS-b-PTMC obtained from Example 21. AZPS-b-PTMC (0.2g) from Example 21 was dissolved in THF to form a 20 wt % solution andthe polymer was precipitated in methanol:acetonitrile (200 ml, 60:40v/v). The precipitated solids and the solvents were collected in acentrifuge tube and the solids were collected by centrifuging at 4000RPM at 0° C. followed by decanting the solvent and drying the solids ina vacuum oven at 40° C. for two hours. Mn (GPC)=10.9 k, Mw=11.3 k,PDI=1.03; Mn (NMR)=AZPS(6.2 k)-b-PTMC(2.9 k), n=57, m=28.

Example 35

Fractionation of AZPS-b-PTMC obtained from Example 22. AZPS-b-PTMC (0.2g) from Example 22 was dissolved in THF to form a 20 wt % solution andthe polymer was precipitated in methanol:acetonitrile (200 ml, 60:40v/v). The precipitated solids and the solvents were collected in acentrifuge tube and the solids were collected by centrifuging at 4000RPM at 0° C. followed by decanting the solvent and drying the solids ina vacuum oven at 40° C. for two hours. Mn (GPC)=22.1 k, Mw=24.2 k,PDI=1.09; Mn (NMR)=AZPS(10 k)-b-PTMC(13.3 k), n=93, m=130.

Formation of AZPS-b-PMTC-Me Block Copolymer Example 36 Synthesis ofAZPS-b-PMTC-Me

To an oven dried 4 ml glass vial equipped with a magnetic stir bar,AZ-PS—OH (0.2 g, 0.0322 mmol, Mn=6200, PDI=1.02, obtained fromAZ-Electronic Materials, Branchburg, N.J.), MTC-Me (0.21 g, 1.20 mmol),and DCM (0.6 ml) were added. The reaction mixture was stirred until theAZ-PS—OH macroinitiator and TMC were completely dissolved in DCM, uponwhich DBU (15 mg, 0.097 mmol) was added. The reaction mixture wasstirred at room temperature for one hour in a glove box. The resultingnon-endcapped block polymer was isolated by precipitating the reactionmixture in methanol. The product was collected in a frit funnel byremoving methanol under vacuum and the resulting solids were redissolvedin THF to form a 20 wt % solution and reprecipitated in methanol. Thesolids were collected in a frit funnel and dried under vacuum at 40° C.for two hours to obtain the resulting compound. Mn (GPC)=15.5 k, Mw=16.8k, PDI=1.08; Mn (NMR)=AZPS(6.2 k)-b-PMTC-Me(5.9 k), n=57, m=58; MTC-Me %conversion: >99%.

Example 37

Fractionation of AZPS-b-PMTC-Me obtained from Example 36. AZPS-b-PMTC-Me(0.15 g), from Example 36 was dissolved in THF to form a 20 wt %solution and the polymer was precipitated in methanol:acetonitrile (150ml, 60:40 v/v). The precipitated solids and the solvents were collectedin a centrifuge tube and the solids were collected by centrifuging at4000 RPM at 0° C. followed by decanting the solvent and drying thesolids in a vacuum oven at 40° C. for two hours. Mn (GPC)=14.4 k,Mw=15.9 k, PDI=1.10; Mn (NMR)=AZPS(6.2 k)-b-PMTC-Me(5.3 k), n=57, m=52.

Example 38

Synthesis of underlayer. To a 100 ml round bottom flask equipped with amagnetic stir bar and an overhead condenser, styrene (Sty, 5.2 g, 49.9mmol), acrylonitrile (ACN, 1.22 g, 23.0 mmol), glycidyl methacrylate(GMA, 0.545 g, 3.84 mmol), AIBN (0.25 g, 1.53 mmol) and THF (20 g) wereadded. The reaction mixture was purged with nitrogen for 15 minutes andwas placed in a preheated oil-bath set at 70° C. for 16 hours. Thereaction was cooled to room temperature and the polymer was precipitatedin hexanes. The product was collected in a frit funnel by removinghexanes under vacuum and the resulting solids were redissolved in THF toform a 20 wt % solution and reprecipitated in hexanes. The solids werecollected in a frit funnel and dried under vacuum at 40° C. for 24 hoursto obtain the resulting underlayer material. Mn (GPC)=10.6 k, Mw=18.0 k,PDI=1.69. The composition of the copolymer was determined by ¹³C inversegated NMR (400 MHz in CDCl₃). Product mole ratio ofSty:ACN:GMA=0.60:0.34:0.06.

Example 39

Preparation of underlayer coated substrate. A solution of underlayermaterial from Example 38 was prepared by dissolving the random copolymerand p-NBT (p nitro benzylsulphonic acid, triflate salt) in a weightratio of 95/5 (w/w) at a concentration of 0.5 wt % in propylene glycolmonomethyl ether acetate (PGMEA). p-NBT as a thermal acid generator wasadded to promote the cross-linking of the copolymer when it was baked inthe form of thin film. This resulting solution was passed though a 0.2micrometer PTFE filter and spin casted on a silicon wafer at 2000 rpmspin rate. After the thin film was formed, the wafer was baked at 215°C. for 2 minutes and cooled to room temperature. A solvent rinse wasthen conducted by casting PGMEA on top of the wafer and letting thePGMEA puddle for 30 seconds prior to spin drying at 2000 rpm for 30seconds. The rinse was intended to remove any excess underlayer materialthat was not crosslinked.

Example 40

Thin film preparation and characterization of as-cast andthermal-annealed PS-b-PTMC of Example 13. A solution of PS-b-PTMCobtained from Example 13 was prepared by dissolving the PS-b-PTMC inPGMEA (1% w/w). The solution was filtered using a 0.2 micrometer PTFEfilter prior to spin coating the solution onto the underlayer coatedsilicon wafer of Example 39 at 2000 rpm. The as-cast thin film wascharacterized by atomic force microscopy (AFM, FIG. 16). The as-castfilm was baked at 170° C. for 5 minutes and cooled to room temperatureto form a thermally annealed film, which was also characterized by AFM(FIG. 17). AFM characterization was performed with a Digital Instruments3100 AFM with a 1 N/m spring constant silicon nitride cantileveroperated in a tapping mode. Scan size and speed were set at 2micrometer×2 micrometer area and 2.5 Hz, respectively. PSD (powerspectra density) data that gave insight into the periodical spacingbetween micro-phase separated structures was processed by the DigitalInstruments software, Nanoscope version 5.30. The characterized AFMheight images of PS-b-PTMC from Example 13 revealed non-uniform surfacesfor both as-cast and thermally annealed samples, with no features on theprotuberant/uneven area and micro-phase separated cylinder structures onthe flat area. The PSD of the as-cast and annealed samples were 22 nmand 23.5 nm, respectively. The PSD numbers indicated the average spacingof the mixture of parallel-oriented and perpendicular-oriented cylinderstructures.

Example 41

Thin film preparation and characterization of as-cast and thermallyannealed fractionated PS-b-PTMC of Example 26 using the procedure ofExample 40 with the PS-b-PTMC of Example 26. The characterized films ofPS-b-PTMC BCP from Example 26 revealed uniform surfaces of micro-phaseseparated cylinder structures for both as-cast and annealed films. Theas-cast film (FIG. 18) fully consisted of perpendicular-orientedcylinder structures with a row-to-row spacing of 16.5 nm as indicated bythe PSD analysis. The annealed film (FIG. 19) revealed more of a mixtureof parallel-oriented and perpendicular-oriented cylinder structures thatgave rise to the PSD number of 19.5 nm. The higher PSD number indicatedthe center-to-center spacing between perpendicular-oriented cylindersinstead of the row-to-row spacing. The center-to-center spacing number(19.5 nm), however, correlated well with the row-to-row spacingcalculation for the hexagonal arrays of perpendicular-oriented cylinders(16.5 nm).

Example 42

Synthesis of AZPS-b-PTMC with DBU catalyst. To an oven dried 4 ml glassvial equipped with a magnetic stir bar, AZ-PS—OH (0.20 g, 0.0322 mmol,Mn=6200, PDI=1.02, obtained from AZ-Electronic Materials, Branchburg,N.J.), TMC (0.246 g, 2.41 mmol) of from Example 4, and DCM (0.60 ml)were added. The reaction mixture was stirred until the AZ-PS—OHmacroinitiator and TMC were completely dissolved in DCM, upon which DBU(about 12 mg, 0.078 mmol) was added. The reaction mixture was stirred atroom temperature for 9.5 hours in a glove box. Aliquots of the reactionmixture were taken at regular intervals to determine the TMC ringopening by 1H NMR analysis and average molecular weight by GPC analysis.After 9.5 hours (570 minutes), the reaction was stopped by bringing thereaction vial out of the glove box and adding DCM (2 ml), acetylchloride (0.1 g, 0.988 mmol), and TEA (0.1 g, 1.28 mmol). The reactionwas further stirred for two hours at room temperature. The resultingpolymer was isolated by precipitating the reaction mixture in methanol.The product was collected in a frit funnel by removing methanol undervacuum and the resulting solids were redissolved in THF to form a 20 wt% solution and reprecipitated in methanol. The solids were collected ina frit funnel and dried under vacuum at 40° C. for two hours to obtainthe resulting compound. Mn (GPC)=19.3 k, Mw=20.5 k, PDI=1.06; Mn(NMR)=AZPS(6.2 k)-b-PTMC(7.2 k), n=57, m=71; TMC % conversion: ˜99%.

Example 43

Fractionation of AZPS-b-PTMC obtained from Example 42. AZPS-b-PTMC (0.2g) from Example 42 was dissolved in THF to form a 20 wt % solution andthe polymer was precipitated in methanol:acetonitrile (200 ml, 60:40v:v). The precipitated solids and the solvents were collected in acentrifuge tube and the solids was collected by centrifuging at 4000 RPMat 0° C. followed by decanting the solvent and drying the solids in avacuum oven at 40° C. for two hours. Mn (GPC)=19.3 k, Mw=20.5 k,PDI=1.06. Mn (NMR)=AZPS(6.2 k)-b-PTMC(6.8 k), n=57, m=67.

Table 9 summarizes the preparations and properties of thepolystyrene-b-polycarbonate block copolymers before fractionation.

Table 10 summarizes the polystyrene-b-polycarbonate block copolymersafter fractionation. A smaller change in Mn of the polycarbonate block(“Delta Mn (PC Block)”) is desirable.

TABLE 9 NMR GPC (Mn, kDa)) Polymer Time Mn Mw PS PC Monomer Vf ExampleName Monomer Catalyst Initiator Temp (hours) (kDa) (kDa) PDI block block% Conv. (PC block) 11 PS-PTMC TMC-4 DBU PS-OH rt 2.5 13.1 14.3 1.09 5.54.8 86 0.41 12 PS-PTMC TMC-3 DBU PS-OH rt 4 13.5 15.6 1.15 6.5 4.5 980.35 13 PS-PTMC TMC-3 DPP PS-OH rt 15 17.9 20.1 1.12 9.4 11.5 94 0.49 14PS-PTMC TMC-4 DPP PS-OH rt 20 11.9 12.9 1.07 5.5 5.4 99 0.44 15 PS-PTMCTMC-4 DPP PS-OH rt 20 16.1 17.5 1.08 5.5 6.3 99 0.47 16 PS-PTMC TMC-4DPP PS-OH rt 20 18.5 20 1.08 5.5 7.7 99 0.52 17 AZPS-PTMC TMC-4 DPPAZ-PS-OH rt 16 13.3 13.7 1.029 6.2 7.7 99 0.49 18 AZPS-PTMC TMC-4 DPPAZ-PS-OH rt 16 14.1 14.5 1.029 6.2 7.7 99 0.49 19 AZPS-PTMC TMC-4 DPPAZ-PS-OH rt 12 20 AZPS-PTMC TMC-4 DPP AZ-PS-OH rt 16 14.1 14.5 1.029 6.27.7 50 0.49 21 AZPS-PTMC TMC-4 DPP AZ-PS-OH rt 5 10.5 10.8 1.03 6.2 3.050 0.28 22 AZPS-PTMC TMC-4 DPP AZ-PS-OH rt 21 25 26 1.04 10.0 13.0 530.50 36 AZPS-PMTC-Me MTC-Me DBU AZ-PS-OH rt 1 15.5 16.8 1.08 6.2 5.9 990.43 42 AZPS-PTMC TMC-4 DBU AZ-PS-OH rt 9.5 19.3 20.5 1.06 6.2 7.2 990.48 Vf = volume fraction of the polycarbonate block of the blockcopolymer rt = room temperature PS block = polystyrene block PC block =polycarbonate block (PTMC or PMTC-Me)

TABLE 10 NMR analysis Solvent GPC (Mn, kDa) Delta Polymer Volume Mn MwPS PC Mn Vf Examples Fractionated Solvent Ratio (kDa) (kDa) PDI blockblock (PC Block) PC block 23 Ex. 12 MeOH/ACN 80/20 13.2 15.2 1.15 6.54.4 0.1 0.35 24 Ex. 12 MeOH/ACN 60/40 13.2 15.2 1.15 6.5 4.0 0.5 0.33 25Ex. 12 MeOH/ACN 40/60 14.2 16.3 1.14 6.5 3.6 0.9 0.30 26 Ex. 13 MeOH/ACN40/60 18.5 20.0 1.08 9.4 4.4 7.1 0.27 28 Ex. 14 MeOH/ACN 40/60 11.2 12.11.08 5.5 4.5 0.9 0.39 29 Ex. 15 MeOH/ACN 40/60 14.8 16.1 1.08 5.5 5.31.0 0.43 30 Ex. 16 MeOH/ACN 40/60 17.8 19.3 1.08 5.5 6.5 1.2 0.48 31 Ex.17 MeOH/ACN 60/40 13.5 13.9 1.02 6.2 5.8 1.9 0.42 32 Ex. 18 MeOH/ACN60/40 14.0 14.4 1.03 6.2 6.4 1.3 0.45 33 Ex. 20 MeOH/ACN 60/40 17.2 17.61.02 6.2 7.7 0.0 0.49 34 Ex. 21 MeOH/ACN 60/40 10.9 11.3 1.03 6.2 2.90.1 0.27 35 Ex. 22 MeOH/ACN 60/40 22.1 24.2 1.09 10.0 13.3 0.3 0.51 37Ex. 36 MeOH/ACN 60/40 14.4 15.9 1.10 6.2 5.3 0.6 0.40 43 Ex. 42 MeOH/ACN60/40 19.3 20.5 1.06 6.2 6.8 0.3 0.46 Vf = volume fraction ofpolycarbonate block of the block copolymer PC = polycarbonate block(PTMC or PMTC-Me)

The above examples demonstrate that fractionation of the product blockpolymer using a combination of a non-solvent for the polystyrene blockand a nitrile solvent for the polycarbonate block in a 60:40 to 40:60volume ratio, respectively, was effective in purifying the block polymerfrom polycarbonate homopolymer contaminants that can adversely affectthe self-assembly properties of the block copolymer films. The highestlevel of polycarbonate homopolymer impurity was observed with ROPshaving the highest cyclic carbonate monomer conversion (i.e., 95-99%conversion, Examples 25-32), as evidenced by the change in Mn of thepolycarbonate (PC) block after fractionation (see column labeled “DeltaMn (PC block)” in Table 10). By comparison, ROPs that were stopped at50-53% cyclic carbonate conversion (Examples 33-35 and 43) showedminimal amounts of polycarbonate homopolymer contaminant, as evidencedby the small change in Mn of the polycarbonate block afterfractionation. Therefore, the homopolymer contaminant was formedpredominantly in the later stages of the polymerization when cycliccarbonate monomer conversion was greater than about 70%. The followingexample utilized the above fractionation method to determine an optimumROP reaction time for a given set of ROP conditions used to form theblock polymer.

Example 44

The procedure of Example 18 was followed, scaling the reaction the same,and sampling the reaction mixture at various times during the ROP. Aportion of each crude block polymer sample was analyzed for TMC contentby NMR and for average molecular weight by GPC. Table 11 summarizes theTMC content of each sample and the Mn, Mw and PDI obtained by GPC beforefractionation. Table 11 also includes the number average molecularweight (Mn) of the poly(trimethylene carbonate) (PTMC) block of thediblock polymer as determined by NMR based on the polystyrene (PS) blockhaving an Mn of 6600.

TABLE 11 TMC GPC % (Before Fractionation) NMR Ex. 44 Time Conver- Mn Mw(Mn, kDA) Sample (minutes) sion (kDa) (kDa) PDI PS PTMC 0 0 0.00  6.67.0 1.06 6.6 0.00 1 255 31.00 11.05 11.56 1.04 6.6 2 410 46.50 13.4314.04 1.04 6.6 3.66 3 480 54.75 14.26 14.93 1.04 6.6 4.40 4 560 62.0015.10 15.82 1.04 6.6 5.00 5 635 68.30 15.53 16.35 1.04 6.6 5.57 6 75576.50 16.84K 17.64 1.04 6.6 6.26 7 875 82.70 17.79K 18.60 1.04 6.6 6.77

Another portion of each Example 44 sample was precipitated in MeOH andfractionated using a mixture of MeOH and acetonitrile (60/40 by volume,respectively) according to the above-described procedure. Table 12summarizes the Mn, Mw and PDI of each sample after fractionationobtained by GPC. Table 12 also includes the number average molecularweight (Mn) of the PTMC block after fractionation obtained by NMR basedon the PS block having an Mn of 6600. Table 12 also lists the change inMn of the PTMC block relative to the pre-fractionated sample.

TABLE 12 Delta GPC Mn (After Fractionation) NMR PTMC Ex. 44 Time TMC MnMw (Mn, kDA) Block Sample (minutes) % Conversion (kDa) (kDa) PDI PS PTMC(kDa) 0 0 0.00 1 255 31.00 2 410 46.50 13.0 13.6 1.04 6.6 3.61 0.05 3480 54.75 14.1 14.8 1.04 6.6 4.23 0.17 4 560 62.00 14.84 15.53 1.04 6.64.84 0.16 5 635 68.30 15.67 16.4 1.04 6.6 5.39 0.18 6 755 76.50 17.117.85 1.04 6.6 6.04 0.22 7 875 82.70 17.9 18.57 1.04 6.6 6.40 0.37

The results indicate that samples 6 and 7 have significantly higherlevels of PTMC homopolymer, indicated by the increase in delta Mn from0.18 of sample 5 to 0.37 for sample 7.

Using the above data from Example 44, an optimum reaction time wasdetermined using the following procedure.

Method 2

For a given set of reaction conditions (Example 44), the % TMCconversion was plotted as a function of reaction time in minutes, and asecond order polynomial trendline F(t) was fitted to the data. F(t) isshown in FIG. 1 (graph). In this instance, F(t)=−0.00005t²+0.1352t,having R²=0.9993.

Using F(t) and the quadratic equation, the reaction duration time t₁ at50% TMC conversion (F(t₁)=50) was calculated from the expression50=−0.00005t₁ ²+0.1352t₁. In this instance, t₁=442 minutes.

The first derivative of F(t) has the expression F′(t)=−0.0001t+0.1352 (aline). Table 13 lists the value of F′(t) at each measurement time t.FIG. 2 is graph of F′(t) at as a function oft, showing the linearrelationship.

TABLE 13 Delta Mn NMR PTMC Ex. 44 Time TMC (Mn, kDA) Block Samples(minutes) % Conversion F′(t) PS PTMC (kDa) 0 0 0.00 0.1352 1 255 31.000.1097 2 410 46.50 0.0942 6.6 3.61 0.05 3 480 54.75 0.0872 6.6 4.23 0.174 560 62.00 0.0792 6.6 4.84 0.16 5 635 68.30 0.0717 6.6 5.39 0.18 6 75576.50 0.0597 6.6 6.04 0.22 7 875 82.70 0.0477 6.6 6.40 0.37

The value of F′(t) at t₁ (50% cyclic carbonate conversion) wascalculated as F′(442)=−0.0001(442)+0.1352=0.091.

The duration time corresponding to a 10% drop in F′(442) was calculated,which is 0.9(0.091)=0.0819. This value of F′(t) corresponds to aduration time of 533 minutes.

The duration time corresponding to a 20% drop in F′(442) was calculated,which is 0.8(0.091)=0.0728. This value of F′(t) corresponds to areaction time of 624 minutes.

The ROP can be conducted using a reaction time of about 422 minutes (t₁)to about 624 minutes (t₃), more particularly about 533 minutes (t₂) toabout 624 minutes (t₃) for the given reaction conditions. A ROP reactiontime in this range provides for the most efficient incorporation of thecyclic carbonate monomer into the block polymer and the lowest level ofpolycarbonate homopolymer impurity in the isolated block polymer.

Alternatively, the duration time of the ROP was determined by thefollowing method.

F′(t) was obtained as described above. The change in F′(t), Δ′F(t), wasthen calculated between adjacent measurement times, whereΔF′(t_(n))=F′(t_(n))−F′(t_(n-1)) for adjacent times t_(n) and t_(n-1),wherein t_(n)>0. Table 14 below lists the calculated values for ΔF′(t)for each measurement time t.

TABLE 14 TMC Mn (% NMR PTMC Ex. 44 Time Conver- (Mn, kDA) Block Samples(minutes) sion) F′(t) ΔF′(t) PS PTMC (kDa) 0 0 0.00 0.1352 1 255 31.000.1097 −0.0255 2 410 46.50 0.0942 −0.0155 6.6 3.61 0.05 3 480 54.750.0872 −0.0070 6.6 4.23 0.17 4 560 62.00 0.0792 −0.0080 6.6 4.84 0.16 5635 68.30 0.0717 −0.0075 6.6 5.39 0.18 6 755 76.50 0.0597 −0.0120 6.66.04 0.22 7 875 82.70 0.0477 −0.0120 6.6 6.40 0.37

A scatter plot of ΔF′(t) versus t was made, and a second orderpolynomial D(t)=−0.0000001t²+0.0002t−0.0562 fitted to the data points(FIG. 3). D(t) has a first derivative that approaches zero at about 630minutes (t″=630 minutes). The ROP duration time for the given conditionscan then be set to 0.8t″ to t″, or in this instance about 504 minutes toabout 630 minutes.

Stopping the ROP at the calculated end point favors an isolated blockpolymer having sufficient purity to be used without fractionating thepolymer further. If desired, the isolated block copolymer can be furtherpurified by precipitation in a solvent mixture comprising i) anon-solvent for the block derived from the vinyl polymerizable monomerand ii) a nitrile solvent, wherein the volume ratio of the non-solventto nitrile solvent is 40:60 to 60:40.

Example 45

Using the general procedure of Example 40, a thin film of the blockpolymer prepared in Example 17 was formed. FIG. 20 is an AFM image ofthe as-cast film. The as-cast film shows slight topography in a fewareas indicated by white patches in the AFM height image, but smoothotherwise. These white patches depict elevated areas as compared to restof the film. The AFM image of the as-cast film shows partialself-assembly of the block polymer.

Example 46

Using the general procedure of Example 40, a thin film of the blockpolymer prepared in Example 20 was formed. FIG. 21 is an AFM image ofthe as-cast film. The as cast film is not smooth and shows considerabletopography. The white area indicates elevated features in the AFM heightimage. The film does not show evidence of self-assembly of the blockpolymer.

Example 47

Using the general procedure of Example 40, a thin film of the blockpolymer prepared in Example 21 was formed. FIG. 22 is an AFM image ofthe as-cast film. The AFM image of the as-cast film shows partialself-assembly of the block polymer.

Example 48

Using the general procedure of Example 40, a thin film of the blockpolymer prepared in Example 31 was formed. FIG. 23 is an AFM image ofthe as-cast film. The as cast film shows slight topography in a fewareas indicated by white and red patches in AFM height image, but smoothotherwise. The white patches depict elevated areas, and darker (red)indicates suppressed areas compared to rest of the film. The AFM imageof the as-cast film shows partial self-assembly of the block polymer.

Example 49

Using the general procedure of Example 40, a thin film of the blockpolymer prepared in Example 33 was formed. FIG. 24 is an AFM image ofthe as-cast film. The as-cast film is not smooth and shows considerabletopography. The white area indicates elevated feature in AFM heightimage. The AFM image of the as-cast film does not show evidence ofpartial self-assembly of the block polymer.

Example 50

Using the general procedure of Example 40, a thin film of the blockpolymer prepared in Example 34 was formed. FIG. 25 is an AFM image ofthe as-cast film. The AFM image of the as-cast film shows partialself-assembly of the block polymer.

Example 51

Directed self-assembly of fractionated PS-b-PTMC of Example 34. Atopographical pre-pattern to direct the self-assembly of fractionatedPS-b-PTMC of Example 34 was prepared by exposing a 193i photoresist (JSRAIM7210) film coated on a underlayer-coated substrate using 193 nminterference lithography. The substrate was a silicon wafer coated witha 193 nm anti-reflective ARC29A (Brewer Science) layer. The underlayerdescribed in Example 39 was coated on the anti-reflective layer usingthe general procedure of Example 39. The non-exposed area of thephotoresist was developed in a negative tone using an organic solvent(2-heptanone) developer, resulting in a regular grating pattern having a100 nm half-pitch. This pre-pattern was baked at 200° C. for 3 minutesto make the pre-pattern insoluble to organic solvent. A solution offractionated PS-b-PTMC of Example 34 that was dissolved in PGMEA (1%w/w) was then spin-coated on the pre-pattern at 4000 rpm to form a thinfilm allocated substantially in the trenches of the pre-pattern. Theblock copolymer coated pre-pattern sample was then baked at 170° C. for5 minutes and cooled down to room temperature to let the PS-b-PTMCself-assemble alongside the sidewall of the pre-pattern trenches, asillustrated in layered structure 100 of FIG. 26 (cross-sectionaldiagram). Layered structure 100 shows silicon wafer 101, anti-reflectivelayer 107, underlayer 102, resist topographical features 103 having aheight h′ of 35 nm, trench area 106 having a width z′ of 85 nm betweenfeatures 103, self-assembled block polymer layer having a thickness t′of 21 nm, and phase domains 104 and 105 of the self-assembled blockpolymer located in the trench area 106. Domain 104 represents the PSphase. Parallel cylinder domains 105 represent the PTMC phase. Parallelcylinder domains 105 are embedded in the PS domain 104. The sample wassubjected to a brief RIE etch utilizing a combination of CF₄ and H₂gases to etch the top layer of PS and slightly etch the PTMC domains andenhance the contrast between PS and PTMC domains during SEMcharacterization. The SEM characterization revealed well-alignedPS-b-PTMC of Example 34 in the trenches of the pre-pattern. The top downSEM image of FIG. 27 shows that in the 85 nm-wide trenches, 5 PTMCcylinders aligned parallel to the sidewall revealing 6 aligned PS linesafter etching. From the cross-sectional SEM image, a monolayer ofPS-b-PTMC cylinder block copolymer with a thickness of approximately 21nm was shown to occupy the 35 nm-high trenches. FIG. 28 is a diagramshowing a top down view of layered structure 100 before etch. FIG. 29 isa diagram showing a top down view of layered structure 110, which islayered structure 100 after the etch. Layered structure 110 shows the PSdomains 104 remaining in the trench area 106 after selective removal ofPTMC domains 105. PS domains 104 appear as lines parallel to resistfeatures 103. In this instance, the etch exposes anti-reflective layer102.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. When a range is used to express apossible value using two numerical limits X and Y (e.g., a concentrationof X ppm to Y ppm), unless otherwise stated the value can be X, Y, orany number between X and Y.

The description of the present invention has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiments were chosen and described in order to best explain theprinciples of the invention and their practical application, and toenable others of ordinary skill in the art to understand the invention.

What is claimed is:
 1. A method, comprising: forming a reaction mixturefor a ring opening polymerization (ROP), the reaction mixture comprisinga cyclic carbonyl monomer, a polymeric initiator for the ROP, a ROPcatalyst, and a solvent, wherein the polymeric initiator comprises i) apolymer backbone comprising repeating functionalized ethylene units andii) 1 to 2 nucleophilic groups capable of initiating a ROP of the cycliccarbonyl monomer; allowing the cyclic carbonyl monomer to polymerize byROP until 85% or more of the cyclic carbonyl monomer is consumed,thereby forming a second mixture comprising an initial block polymer,wherein the initial block polymer comprises a first block linked to asecond block, the first block comprising the polymer backbone comprisingrepeating functionalized ethylene units, the second block comprising abackbone derived from ROP of the cyclic carbonyl monomer; precipitatingthe initial block polymer in a solvent mixture comprising i) a firstsolvent which is a non-solvent for the first block, and ii) a secondsolvent comprising a nitrile group, wherein the first solvent:secondsolvent volume ratio is about 40:60 to about 60:40, thereby forming afinal block polymer that is free of, or substantially free of, anypolymer having a chemical structure that contains none of the polymerbackbone of the polymeric initiator.
 2. The method of claim 1, whereinthe cyclic carbonyl monomer is trimethylene carbonate.
 3. The method ofclaim 1, wherein the ROP is performed at ambient temperature.
 4. Themethod of claim 1, wherein the first solvent is an alcohol.
 5. Themethod of claim 1, wherein the second solvent is acetonitrile.
 6. Themethod of claim 1, wherein the polymeric initiator is a polystyrenecomprising one hydroxy end group.
 7. The method of claim 1, wherein theblock polymer self-assembles to form cylindrical domains of the secondblock in a matrix of the first block.
 8. The method of claim 1, whereinthe block polymer self-assembles to form spherical domains of the secondblock in a matrix of the first block.
 9. The method of claim 1, whereinthe block polymer self-assembles to form lamellar structures comprisingalternating domains of the first block and the second block.
 10. Amethod, comprising: i) providing a mathematical function F(t) for a ringopening polymerization (ROP) of a cyclic carbonyl monomer, wherein F(t)expresses an amount of consumed cyclic carbonyl monomer as a function ofROP duration time t for given reaction conditions, the ROP utilizes areaction mixture initially comprising the cyclic carbonyl monomer, apolymeric initiator for the ROP, a ROP catalyst, and a solvent, thepolymeric initiator comprises i) a polymer backbone comprising repeatingfunctionalized ethylene units and ii) 1 to 2 nucleophilic groups linkedto respective end groups of the polymer backbone, the nucleophilicgroups capable of initiating the ROP of the cyclic carbonyl monomer,F(t) has a duration time t₁>0 corresponding to 50% consumption of thecyclic carbonyl monomer, F(t) has duration times t₂ and t₃ whereint₃>t₂>t₁, F(t) has a first derivative designated F′(t), F′(t) at t₁ hasa value F′(t₁)=m, wherein m is a number >0 F′(t) at t₂ has a valueF′(t₂)=0.9 m, and F′(t) at t₃ has a value F′(t₃)=0.8 m; ii) conductingthe ROP of the cyclic carbonyl monomer using the given set of reactionconditions; and iii) stopping the ROP at a ROP duration time of about t₁to about t₃, thereby forming a second mixture comprising a final blockpolymer capable of self-assembly, wherein the final block polymercomprises a first block linked to a second block, the first blockcomprising the polymer backbone comprising repeating functionalizedethylene units, the second block comprising a backbone derived from ROPof the cyclic carbonyl monomer, and wherein the second mixture is freeof, or substantially free of, any polymer having a chemical structurethat contains none of the polymer backbone of the polymeric initiator.11. The method of claim 10, wherein stopping the ROP comprises treatinga living end group of the second block with an alcohol protecting agent.12. The method of claim 10, wherein the alcohol protecting agent is acompound selected from the group consisting of active esters, acidhalides, acid anhydrides, isocyanates, ether forming agents,perfluorinated derivatives of any of the foregoing compounds, andcombinations thereof.
 13. The method of claim 10, wherein stopping theROP comprises precipitating the final block polymer in a solventmixture, the solvent mixture comprising i) a first solvent that is anon-solvent for the first block and ii) a second solvent comprising anitrile group, wherein the first solvent:second solvent volume ratio isabout 40:60 to about 60:40.
 14. The method of claim 10, wherein the ROPcatalyst is a phosphate diester.
 15. The method of claim 10, wherein theROP catalyst is diphenylphosphate (DPP).
 16. The method of claim 10,wherein the cyclic carbonyl monomer is a cyclic ester.
 17. The method ofclaim 10, wherein the cyclic carbonyl monomer is a cyclic carbonate. 18.The method of claim 10, wherein no cyclic carbonyl monomer is added tothe reaction mixture after the ROP is initiated.
 19. A method,comprising: i) providing a mathematical function F(t) for a ring openingpolymerization (ROP) of a cyclic carbonyl monomer, wherein F(t)expresses an amount of consumed cyclic carbonyl monomer as a function ofROP duration time t for given reaction conditions, the ROP utilizes areaction mixture initially comprising the cyclic carbonyl monomer, apolymeric initiator for the ROP, a ROP catalyst, and a solvent, thepolymeric initiator comprises i) a polymer backbone comprising repeatingfunctionalized ethylene units and ii) 1 to 2 nucleophilic groups linkedto respective end groups of the polymer backbone, the nucleophilicgroups capable of initiating the ROP of the cyclic carbonyl monomer, andF(t) has a first derivative F′(t); ii) providing a mathematical functionD(t) expressing change in F′(t) between adjacent ROP duration times,designated ΔF′(t), as a function of ROP duration time t, wherein i)ΔF′(t_(n))=F′(t_(n))−F′(t_(n-1)) for adjacent duration times t_(n) andt_(n-1), t_(n)>t_(n-1), and n is a positive integer greater than orequal to 1, ii) D(t) has a first derivative designated D′(t), and iii)D′(t) has a duration time t′>0 wherein D′(t′)=0; iii) conducting the ROPof the cyclic carbonyl monomer using the given reaction conditions; andiv) stopping the ROP at a polymerization duration time of 0.8t′ to t′,thereby forming a second mixture comprising a final block polymercapable of self-assembly, wherein the final block polymer comprises afirst block comprising the polymer backbone comprising repeatingfunctionalized ethylene units, the first block being linked by a polymerchain end group to a second block comprising a polymer backbone derivedfrom the cyclic carbonyl monomer, and wherein the second mixture issubstantially free of any polymer having a chemical structure thatcontains none of the polymer backbone of the polymeric initiator. 20.The method of claim 19, wherein the D(t) is a polynomial expressionhaving an R-squared value of about 0.85 to 1.0.
 21. A method of forminga layered structure, comprising: forming a mixture comprising a solventand the final block polymer formed by the method of claim 1; applyingthe mixture to a pre-patterned surface of a substrate, thereby forming afirst structure, the pre-patterned surface capable of guidingself-assembly of the final block polymer wherein self-assembly of thefinal block polymer comprises phase separation of a first block of thefinal block polymer from a second block of the final block polymer toform first domains comprising the first block and second domainscomprising the second block, the first domains not being miscible withthe second domains; removing the solvent from the first structure,thereby forming a second structure comprising the final block polymerdisposed on the surface of the substrate; and allowing the final blockpolymer of the second structure to self-assemble, optionally assistedwith heat, thereby forming the layered structure, the layered structurecomprising the self-assembled final block polymer disposed on thepre-patterned surface.
 22. The method of claim 21, wherein thepre-patterned surface of the substrate comprises an underlayercomprising a copolymer derived from styrene, acrylonitrile, and glycidylmethacrylate.
 23. The method of claim 21, wherein the self-assembledfinal block polymer comprises an array of cylindrical structures of thesecond block in a matrix of the first block.
 24. The method of claim 21,wherein the self-assembled final block polymer comprises a linear arrayof lamellae comprising domains of the second block alternating withdomains of the first block.